October 2018 Weather Recap: Started Out Like September, Ended Like It Was November

 

 

Although October wasn't far from average in terms of its overall temperature, few would think of it as merely average as temperatures in the first eleven days of the month, comparable to the start of September, were followed by nearly three weeks of temperature more like early November.  Through the 11th temperatures were ten degrees above average (high/low of 75°/65°), then the rest of the month was nearly twenty degrees colder (57°/45°), and four degrees below average.  Another contrast was between the departure from normal of the month's average high, which was a titch below average (-0.3 degrees), and the average low, which was nearly two degrees milder than average (+1.9 degrees).  And despite it being 0.8 degrees above average, this was the chilliest October in seven years.

Additional points of interest:

• Similar to August and September, the difference between October's average high and low (i.e., diurnal variation) was one of the smallest on record for October - 11.6 degrees (the average is 15.4 degrees).  In the past 100 years only October 2012 had a smaller variation.

• Just a year after the latest date for a low in the 70s occurred (on 10/9) a new mark was set this year when a low of 71° (five degrees warmer than the average high for the date) was reported on the 10th.

• The month was well above average in terms of days with lows of 60° or milder (eleven).  Only October 1879 (thirteen), 2012 (warmest October on record) and 2007 had more lows of 60+.  And this October's eleven days were consecutive (Oct. 1-11), which set a new October record and included five days in a row with mean temperatures that were ten or more degrees above average.  However, despite these balmy conditions just one day, 10/10, had a high in the 80s (80°).

• During the chilly portion of the month there were a dozen days with highs in the 50s, the most since 2009 (the typical number is eight).  And the number of lows in the 30s was three, the most since 2011 (the chilliest reading was 38°).

• The high of 64° on Halloween (five degrees above average) was the month's mildest reading since 10/15 and the first Halloween to have temperatures in the 60s in five years.

• Finally, much of October's 3.59" of rain (the smallest amount in five years) came from the remnants of catastrophic hurricane Michael on 10/11-12, which brought 1.27", and a nor'easter on 10/27 that produced 1.29".  On 10/20 the year's total precipitation passed 50 inches, and by the end of the month 51.42" had been measured, which is close to two inches more than what falls in a typical year.  This ranks as the the ninth greatest amount of precipitation (since 1869) through the end of October.

Here are recaps of previous Octobers:

2017

2016

Comments

[William]

So far this year, there have been 130 days with measurable precipitation up to and including Halloween, the most ever in the first ten months of a year, besting the previous record from 2003 by six days and this was twenty-two fewer than 1996's current annual record number. even if 2018 would experience no rain and/or snow through mid November, its year to date record number of such days would still stand.

[William]

previous to 2018, never before have the following things happened. January began with eight highs of 32° or colder, July began with five lows of 76° or warmer, October began with eleven lows of 60° or warmer and February ended with ten lows of 36° or warmer. Additionally, September had seventeen lows of 67° or warmer (also a monthly first) and this year joined 1988 as the only two Augusts with lows of 70° or warmer during all of the first eighteen days of the month.