Like the month preceding it, May 2019 was characterized by a surfeit of rainy days. There were 19 with measurable rain, which tied December 1972 and May 1973 for the second greatest number for any month. (The most days, 20, occurred in July 1871 and May 1888). However, May 2019 distinguished itself by having more rain than those other months (see chart below). The amount that fell, 6.82", made this May the 12th rainiest on record. Although it had one more day of rain than April (its 18 days was a record for April), nearly two-and-a-half inches more rain fell. But despite the high frequency of rain, much of it occurred on just five days: 1.31" on 5/5; 1.32" on 5/12; 0.70" on 5/13; 0.80" on 5/29; and 0.95" on 5/30.
In addition to the well above average number of rainy days, this May will also be remembered for the damp and unusually cool conditions on Mother's Day and the two days after. 2.32" of rain fell on these three days (1.32" of it on Mother's Day) and the average high/low of 53°/43° was 14 degrees cooler than average. By contrast, the Memorial Day weekend was mostly nice, the exception being later in the afternoon on Sunday when clouds moved in and there was an hour of heavy showers. The three-day weekend's average high/low was 79°/60°, four degrees above average, and featured the warmest reading of the month, 86° on Sunday. (The warmest mean temperature, however, occurred on 5/20, one week before Memorial Day, with a high/low of 85°/66°).
Temperature-wise, the month was average (officially, 0.2 degree below average), with the first half of May three degrees below average while the second half was two degrees above average. (If the chilly three-day period from May 12-14 were taken out, the month would have been 1.3 degrees milder than average.) Seven days were five or more degrees above average while six were five or more below average. Four days with highs in the 80s were balanced by four days with lows in the 40s, both fewer than the month's average (of seven and six days, respectively).
Finally, there was an eight-day streak of rainy days (May 10-17) that had 2.56" of rain. This was just the thirteenth eight-day steak since 1900. Coincidentally, last May had rain on seven of eight days around the same time of the month (May 12-19), which amounted to 2.14". And Mother's Day both years was cool (59°/43° this year, 54°/52° in 2018).
Here are recaps of the previous four Mays: