After experiencing its second mildest April, May in New York was cooler than average. Despite this cool down, it had three days in the 90s, the first time that's happened in May since 2001. These days were consecutive, from May 17-19, with highs of 90-92-91. However, what made the month unique was the fact that it was the first May to have 90-degree days - but no days in the 80s. It was also the coolest of any May that had three or more 90-degree days (see chart below). Overall, the month was 1.3 degrees cooler than average, making it the coolest May in nine years. Interestingly, despite the 90-degree days, what made the month below average was its average high temperature, which was 2.6 degrees below average; the average low, however, was in-line with the 30-year average.
- After the three-day heat wave ended on 5/19, the remaining twelve days of the month had an average high of just 67° (with highs on four of the days in the 59°-61° range). Only six days all month had an above-average daily mean temperature. (Without the month's three 90-degree days, the average high would have been five degrees below average.) Memorial Day, with a high of 61°, was the coolest since 2003 (temperatures in the afternoon were only in the upper 50s). And although Mother's Day was somewhat cooler than average, it was milder than Memorial Day (high of 67°).
- A typical May is 9.4 degrees warmer than April, but this year it was just 3.9 degrees milder. Only in 1945 was May's average temperature closer to April's (a 3.6-degree difference).
- The rainstorm of 5/5 flooded the City with 3.02" of rain, a record for the date. Most of it poured down in a three-hour period between 11AM and 2PM. This was New York's biggest rainfall in three years, and May's fifth biggest daily rainfall total (tied with a storm on May 8, 2013). Eight days later another significant rainfall soaked the area, with 1.61" measured, but unlike 5/5's deluge, this storm's rain fell for an extended period, from daybreak until midnight. The day's amount was just 0.05" shy of the record for the date. In total, 6.38" of rain was measured in Central Park during May, making it the wettest May since 2013, and second wettest of the 21st century (and fifteenth wettest among all Mays). The rainstorms of 5/5 and 5/13 accounted for nearly three-fourths of the month's rainfall.
Other May recaps from previous years: