New York City Weather Archive

Looking Back at New York's Weather: August 14

 

1944

Trend line of today's very warm low and those of the previous three days: 77(today)-76-75-74. 

1988

Today was the hottest day of a very hot summer, with a high/low of 99/80, fourteen degrees above average. 

 

1989

Seven inches of rain fell in the past four days.  And today 0.95" poured down in a one-hour period (6-7PM).  This was the first rain on this date in 11 years.

1994

Today, with a high of 91°, was the last 90-degree day of the year.  In total, there were nineteen days with highs in the 90s this year, two more than average (but half as many as last year).

1995

For the third year in a row the high reached into the 90s on this date.

1999

The 0.78" of rain that fell today was the first significant rain since May 24.  In the past eighty-one days, less than one inch fell - the longest such streak in any year since 1900. 

2003

It was sunny and hot (91°) when the power went out late in the afternoon throughout New York; it was NYC's third major blackout.  For much of the City the electricity remained off until the following afternoon.

 

2005

After a sizzling high of 96° (the fourth day in a row with highs in the mid-to-upper 90s) a strong thunderstorm dumped 3.11" of rain during the evening.  Two especially heavy periods of rain occurred between 6-7PM, when 1.70" fell (including 0.82" in fifteen minutes), and 9-10PM, when 0.83" came down.  Today's rain accounted for much of the month's rainfall.  Up until today just 0.09" of rain had fallen in the past four weeks.

2011

Nearly six inches of rain flooded the area, more than double the amount predicted.  Counting 0.56" that would fall early the next morning, total rainfall from the storm measured 6.37", the fourth biggest rainstorm in the past 100 years.  (Less than two weeks later Hurricane Irene would dump 6.88".)  East of NYC, areas around Long Beach, on the south shore of Long Island, received eleven inches of rain.

 

  

 

 

 

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

Lackluster Heat Waves

This post was inspired by this week's rather tepid four-day heat wave (Aug. 5-8), which had an average high of 90.8 degrees (with highs of 91, 92, 90 and 90).  Of the 66 four-day heat waves that have occurred since 1870 only one, in July 1896, had a lower average high, 90.3 degrees.  (2018's low-grade heat wave matched one in August 2009.)  On average, four-day heat waves have had an average high close to 94°.  (The hottest four-day heat wave on record took place in the summer of 2010, when the high temperature from July 4-7 was 99.5 degrees.)

 

 

 

 

However, the story changes when low temperatures are included in the analysis.  For example, this August's heat wave had an average low of 75.0 degrees, which was 1.3 degrees warmer than the average four-day streak and warmer than two-thirds of the four-day heat waves examined.  When combined with the average high, the mean temperature ranked as 27th coolest - quite a difference in ranking compared to its average high.  (This follows the weather storyline of this century whereby nighttime temperatures in New York are warming more than daytime temperatures.)

 

 

Finally, while the typical four-day heat wave had a 20-degree difference between its high and low, this August's was 15.8 degrees apart, which was the third smallest diurnal variation of the heat waves studied (a heat wave in July 1995 had the smallest, 14.7 degrees, while the second smallest was in July 1870).  

Stuck in the 70s

Despite what the headline suggests, this post isn't about people obsessed with 1970s pop culture.  Rather, it's a discussion about days that have had both high and low temperatures in the 70s.  Since 1900 these type of days have occurred infrequently - about once or twice each year (a typical year averages 35 days with lows in the 70s).  28 years have never registered such a day, 44 have had one instance; the most days in one year was nine, which happened back in 1905.  (More recently, 2017 was one of the years with the most, with five occurrences.)  Temperatures stuck in the 70s usually occur when tropical air is in place, the day is hazy/overcast and rain is in the air. 

 

FURTHER DETAILS

• The warmest low in the 70s to be accompanied by a high temperature below 80° is 74°, which has happened twice - first in August 1901 and then seventy-two years later in August 1973.  Both dates had a high of 79°.  (For reference, the average high when lows are between 70°-74° is around 86°).
• The most consecutive days with temperatures in the 70s all day was five, in 1905 (Aug. 30-Sept. 3).
• The most consecutive years without any "all-70" days is four, from 1962 to 1965 (and six out of seven years from 1962 to 1968).  By contrast, there were 20 of these days in the three-year period 1905, 1906 and 1907; they had nine, five and six of these days, respectively.
• The first decade of the 20th century had more "stuck in the 70s" days than the next three decades combined (38 vs. 37).  Our current decade so far has had 20 occurrences (thru the end of July 2018).
• The latest occurrences for a high/low in the 70s were in 2017, on Oct. 8 and 9 (the 9th is also the latest date for a low in the 70s).  The earliest occurrences were on June 4 and 5 in 1960.
• One out of four of these days either had no measurable rain (half were before 1935) while another one out of four received more than a half-inch of rain.  The greatest rainfall to occur was in 1990 when 4.64" fell on Aug. 10 (the high/low was 76/70).  Two other days with substantial rainfall were associated with Hurricanes Connie and Irene, in Aug. 1955 and Aug. 2011, respectively.

 

July 2018 Weather Recap: Hot Temperatures, Followed by Torrents of Rain

If July 2018 were a cocktail its ingredients would be one part heat, three parts rain.  After a hot start, with temperatures nine degrees above average during the month's first five days (average high/low was 92/78), the rest of July was seasonably warm, which moderated the month's average temperature to 1.1 degree above average.  As for the rain, after a dry start, with just 0.24" measured through July 11, the skies opened up and the rest of the month was very rainy, with 7.21" measured.  With 7.45" in total this was the rainiest month in more than four years, since April 2014, and the rainiest July in fourteen (and the fourteenth wettest July on record).

 

In late July there were seven days in a row (July 21-27) in which measurable rain fell.  This was the fourth streak of six days or more this year, joining 1989 as the only two years since 1900 with four streaks of six days or longer.  (Besides the persistent rain, dew points throughout this week-long period were in the uncomfortable 72°-74° range.)

 

 

The seven-day streak with rain was the first since 2012, but this year's had considerably more rain (2.89" vs. 0.86").  The last day streak of seven days or more with more rain was in May 2009, when 3.81" fell.

 

Downpours on 7/12 and 7/30 were confined to upper Manhattan; Central Park had 0.71" and 0.37", respectively, but my neighborhood, Greenwich Village, four miles south of the park, was dry.  And during the afternoon of 7/17 Manhattan was the bulls-eye for torrential rain from a severe thunderstorm, with 2.24" pouring down in little more than an hour.  Conversely, on 7/27 thunderstorms during late afternoon thru evening produced more than an inch of rain in most parts of the metro area (and 3-5" in parts of east-central NJ) but Central Park had only 0.25". 

 

July's rainfall in Central Park was considerably more than the three other reporting sites in the metro area:

 

 

 

Other July observations: 

• Four of the first five days in July had highs in the 90s; the only one that didn't was the 4th of July, but its high of 86° was the warmest reading on this holiday in five years.  However, due to its very warm low of 77°, the mean temperature was the warmest since 2010.

 

 

• Thirteen days in a row (July 8-20) had highs of 80° or warmer, the longest such streak since one of 19 days in August 2016.  (The record is 62 days in a row, set three years ago.)

• What was most impressive about the hot beginning to July were the low temperatures, all of which were 76° or warmer.  This happens almost as infrequently as five-day streaks with highs of 95°+.

• This was the ninth July in a row with no lows in the 50s, the longest such streak in the years since 1900.  Before 1980 more than half of Julys had at least one low in the 50s, but since 1980 that portion has fallen to 25%.

• By July 25 the month had picked up more rain than the combined amount in May and June (6.80" vs 6.64").

 

Here are links to previous July recaps:

2017

2016

2015

2014

 

Comparing Central Park's Weather Observations With Those of New York's Three Airports

New York City's official reporting site for weather conditions is located in Central Park, but LaGuardia and Kennedy Airports also collect data, as well as Newark Liberty Airport in New Jersey (the airports are 7, 16 and 27 miles away from Central Park, respectively).  Central Park is one of the few reporting sites in the US not located at an airport.  Although the park is surrounded by the "heat island" of Manhattan, its temperatures are influenced by the grass and trees, which hold humidity more than the concrete surroundings of airports.  As a result, afternoon temperatures in the summertime don't rise as much as they do at the three airports, and nighttime temperatures don't fall as much during the winter or summer. 

 

I've looked at five statistics, which cover temperatures and precipitation for the 2000-2017 period.  Of the four weather stations, Central Park averages the most days with highs of 32° or colder and receives the most precipitation while Newark is tops in the number of 90-degree days, lows of 32° or colder and snowfall. 

 

HIGHS OF 90°+

Central Park: Averages 15.6 days (the biggest difference between CPK and Newark was in 2006, when CPK had only eight days, 50% below average, while Newark had 27, an average number) 

Newark: 27.1 (it reported the most in all but one year)

LaGuardia: 21.2 (reported the most in 2007)

Kennedy: 11.5

 

HIGHS OF 32° OR COLDER

Central Park: Averages 17.9 days (it had the most of the four stations in ten years, and three first-place ties)

Newark: 16.2 (reported the most in one year, and one first-place tie)

LaGuardia: 16.4 (reported the most in two years, and one first-place tie)

Kennedy: 16.2 (reported the most in two years, and one first-place tie)

 

LOWS OF 32° OR COLDER

Central Park: An average of 68.8 days

Newark: 81.1 (had the most in all but two years)

LaGuardia: 63.6

Kennedy: 75.3 (had the most in two years)

 

ANNUAL PRECIPITATION

Central Park: 50.58" (half of the years had 50"+; reported the most in every year but two)

Newark: 46.41" (four years had 50"+; reported the most in one year, 2017)

LaGuardia: 45.68" (six years had 50"+; never reported the most)

Kennedy: 43.76" (three years had 50"+; reported the most in one year)

 

ANNUAL SNOWFALL

Central Park: 33.6" (50"+ fell in three of the years; had the most of all the sites in two years)

Newark: 35.2" (four years had 50"+; had the most in half of the years of the period, and tied with CPK in 2010)

LaGuardia: 32.8" (two years had 50"+; had the most in six years, including the last three)

Kennedy: 29.4" (one year had 50"+; no year had the most of the four stations)

 

 

 

Save

June 2018 Weather Recap for New York

Following an April that was significantly colder than average, by 3.6 degrees, and a May that was 4.5 degrees milder than average, June was "just right" as it was close to average, 0.2 degrees above average.  This was the closest to average for any month since June 2015 (0.2 below average).  However, despite the month being average overall, the first half was cooler (and drier) than average while the second half was warmer (five days had highs of 88° or hotter) and wetter (relative to the first half, since the amount that fell was average).  Here are a few other observations of interest: 

 

• Father's Day had a high of 91°, which was 37 degrees hotter than Mother's Day (typical difference between the two holidays is thirteen degrees).  It joined Father's Day 2010 as having the greatest difference in high temperature from Mother's Day (going back to 1960).  Also, this was the first Father's Day with a high in the 90s in twelve years (and the seventh since 1960).

• The hottest day of the first half of the year occurred on the last day of the period as the high reached 93° on 6/30. (The second half of the year began with a high of 96° on 7/1).

• Rainfall was below average, 3.11" vs. a norm of 4.41".  Three-fourths of this amount fell in the last two weeks of the month.  And much of it, 1.36", fell on 6/28, highlighted by the downpour during the evening rush hour, which saw 0.93" pour down in about an hour.

• This storm brought to mind the severe thunderstorm of 5/15 that snarled rush hour traffic.  However, despite producing less rain (0.58") it was characterized by destructive winds that killed five people who were struck by falling trees.

• June was the closest to average a month has been since June 2015, which was 0.2 degrees below average.  Of the twelve months that have been 0.2 degrees or closer to average since 2000, five of them have been in June.

 

 

 

 

 

No Thunderstorms in Central Park for the Past 15 Years? So Says the National Weather Service

I've lived in Manhattan since 1981 so I can attest to the fact that we get our fair share of thunderstorms; through 1995 the average number each year was nineteen.  However, while doing research on thunderstorms, I was very surprised to discover that since 1996 only three were reported in Central Park (and none since 2003).  This is according to NOAA's annual Local Climatological report for CPK (which is the official reporting site for New York City).  Yet, during these same years the reporting stations at LaGuardia, Kennedy and Newark airports each averaged 25 per year.  I thought, perhaps, this was just an egregious oversight, so I contacted NOAA and I was told that it wasn't an error but, rather, the result of "automation and a lack of human augmentation since the mid 1990s."

 

I was taken aback by this explanation.  So, the most populous city in the nation no longer reports the incidence of thunderstorms because a human can't be found to do it?   What added to my consternation was that the "Reference Notices" section found in the monthly and annual reports makes no mention that thunderstorms are no longer reported, nor is there an asterisk in the report's month-by-month line for thunderstorms explaining why the number is '0' every month.  Confounding me further is the fact that an annual average is still reported - a number that grows smaller each year since all of the years with no thunderstorms reported are factored in.  So the most current average listed, 11.1, is completely bogus. 

 

 

Of course, in the grand scheme of things a statistic indicating how often thunderstorms occur is not a crucial one (and it should be noted that any rainfall from a thunderstorm is reported).  However, what troubles me is that there is no explanation that thunderstorms are no longer reported.  Someone not familiar with the NYC climate may think the City actually gets no thunderstorms (and not be aware measurement sites at the three airports collect such information).  And as for the "lack of human augmentation" - isn't that what interns are for?  

 

 

Although thunderstorms are no longer reported in Central Park, the way it is displayed on NOAA's annual summary leaves the impression that they are, but there just weren't any storms in 2017.

 

Curiously, the end of tracking thunderstorms in Central Park coincides with the reporting of days of Heavy Fog for the first time.  In other words, before 1996 the average number of days each year with heavy fog reported (1/4 mile or less) was zero, but since 1996 there have been, on average, 14 such days.  It seems an odd coincidence that the jump in the number of foggy days somewhat coincides with the number of thunderstorms before 1996 while the number of thunderstorms in the present day is what the number of foggy days used to be before 1996.      

Comparing High Temperatures on Mother's and Father's Day

Since Father's Day is about five weeks later than Mother's Day its high temperature is, on average, about thirteen degrees warmer (82° vs. 69°).  However, in 2018 there was a huge disparity in the temperatures as Father's Day had a sizzling high of 91° while Mother's Day's was only 54°.  This 37-degree difference tied 2010 for the greatest difference in temperature between the two holidays (and there was a 36-degree difference in 1994).  However, not every Father's Day has been warmer.  Since 1960 there have been eight Mother's Days with warmer highs (most recently in 2014), with the greatest difference being 28 degrees in 1970.  And sometimes the two holidays have similar readings; for example, in 2000 and 1974 they had the same high temperature.

 

 

 

May 2018 Weather Recap - Big Rebound From April

After suffering through the chilliest April in more than 40 years May reversed course and ranked among the ten warmest, ranking sixth (4.5 degrees above average).  The month's unseasonable warmth began right out of the gate as May 1 saw a high of 80° followed by back-to-back days with highs in the 90s.  This was one of the warmest beginnings to May on record (see chart below).  There were also three days later in the month with highs of 88° (5/17), 89° (5/26) and 89° (5/29).  The last time May had five days with highs of 88° or hotter was in 1991 (which was the warmest May on record). 

 

After the three previous months each had more than five inches of precipitation, May was drier than average, with 3.55" of rain measured.  However, there was a period in which seven days out of eight had rain (May 12-19); this included a severe thunderstorm on 5/15 that moved through during the evening rush hour (five people in the metropolitan area were killed by falling tree limbs).

 

Twelve days had highs of 80° or warmer, eight days were 10 degrees or more above average and three days had lows in the 70s.  And although May 2 and 3 had highs in the 90s, the most uncomfortable day was May 26, which had a heat index of 93° (its  high was 89°).  By contrast, May 2 and 3 had very low humidity and their "feels like" temperatures were lower than the air temperature.  Only six other Mays have had three or more lows in the 70s (since 1930), with two of them being in 2016 and 2015.

 

Balancing the two days in the 90s were two days with highs in the 50s - May 13 (Mother's Day) had a high of 54° and May 19 had a high of 56°.

 

Last May was just 3.9 degrees warmer than April, the second closet the two months have been  (closest was 3.5 degrees in 1945).  By contrast, this May was 17.4 degrees warmer than April, the seventh furthest from April (furthest was 18.1 degrees in 1944).  May is typically 9.3 degrees warmer than April.

 

 

 

Here are links to recaps of previous Mays: May 2017, 2016 and 2015.

 

April 2018 Weather Recap - Chilly, Snowy, Rainy

Like four of the past five months, April was colder than average.  (February, the mildest on record, was the outlier.)  This was the chilliest April since 1975, 3.5 degrees below average.  Eight days had mean temperatures ten degrees or more colder than average (and half of the month's days were five degrees or more below average).  Just three days had highs of 70°+, the fewest since April 2000.  Two of them were back-to-back: 82° and 77° on 4/13 and 4/14.  Earlier that week the month's coldest temperature, 32°, was posted on consecutive days, on-par with what the coldest reading is during a typical April (33°).  However, the number of days with highs chillier than 50° (nine) and lows in the 30s (sixteen) was well above average (three and five days, respectively). 

 

April was also a wet month, with 5.78" of precipitation measured, making it the third month in a row to receive more than five inches (5.83" fell in February, 5.17" in March).  The last time this occurred was August-October 2011.  More than half of the month's precipitation fell during a rainstorm on 4/15-16 that dropped 3.29", the biggest deluge since April 30, 2014.  Finally, Easter, which fell on 4/1, was sunny and pleasant, with a high of 60°.  However, 5.5" of snow fell the next morning (forcing postponement of the Yankees' home opener).  This was the biggest snowfall in April since 1982.

 

 

April 2018 was just one of three Aprils since 1970 to have an average temperature below 50.0 degrees (coming in at 49.5 degrees).  Before 1970, however, April temperatures this cool were much more common, with half of the Aprils between 1869 and 1969 being that chilly.  Therefore, when compared to all Aprils, this April ranks as 44th coolest overall.  Finally, March and April 2018 combined were the coldest first two months of meteorological spring since 1984, and the third coldest in the years since 1970.

 

For recaps of the past two Aprils double-click here: April 2017 and April 2016 

 

 

 

 

 

 

 

Biggest Warmups Following A Snowstorm

Less than 12 hours after the the last snowflakes fell from the 8.4" snowstorm of March 21-22, the temperature rose to 50° later that afternoon.  This was the greatest rebound in temperature following a snowfall of six inches or more since 1915 (when the high reached 51° the day after a snowfall of 10.2" on April 3).  Looking at lesser snowfalls (between two and six inches), there have been six that were followed by even milder temperatures, with the the warmest reading being 58° the day after a snowfall of 2.8" on March 13, 1943.  (Coincidentally, in March 1964, on the same dates as this year's 8.4" snowfall, a high of 50° was also reached the afternoon following a snowfall of 4.9".)  And looking at major snowstorms (accumulations of a foot or more), the biggest warm-up came after the 16-inch snowstorm of Dec. 20-21, 1948, when the high reached 42° on the afternoon of the 21st.

 

Going back to 1900, there have been five snowfalls of six inches or more that have been followed by a high of 45° or milder (either during the afternoon of the day of the snowfall or, if snow continued in the PM hours, the following day).  By contrast there have been twenty snowfalls between two to six inches that have been followed by temperatures of 45+.

 

 

 

Previously I posted an analysis that examined significant snowfalls that occurred the day after mild temperatures.  It can be found here.

 

Snowy day in SoHo (March 21, 2018)