May 2024 Summary – Warmer and Wetter Than Average

Overcast of lenticular stratocumulus clouds photographed looking southwest from the Blue Hill Observatory on 30 April 2024. Photo by BHO Chief Observer Matt Douglas.

Blue Hill Observatory May 2024 Summary: 

May temperature and precipitation were above average with near average sunshine. The approximated 24-hour mean temperature for the month of 57.6 deg F was 2.1 degrees warmer than the 1891-2020 130-year average for May, and it was 0.9 degrees warmer than the 1991-2020 30-year average. The average maximum temperature of 67.7 deg F was 0.9 degrees warmer than the 30-year normal. The average minimum temperature of 49.8 deg F was 1.6 degrees warmer than the 30-year normal, which tied as the ninth warmest on record. The warmest temperature reached 88F on the 22nd, and the lowest temperature was 39F on the 11th. There were no daily temperature records during May. The total precipitation was 5.86 inches, which was 2.04 inches more than the 30-year normal. The greatest amount in 24 hours was 1.47 inches on the 15th-16th, and periods of heavy rain and thunderstorms brought 1.41 inches of rain on the morning of the 30th. There were four thunderstorm days during May, which was one more than average. There was no snowfall during May, and the final 2023-2024 snowfall was 26.8 inches, which was the ninth lowest seasonal snowfall record.  The mean wind speed was 10.3 mph, which was the second lowest on record for May, and the prevailing wind direction was from the east-northeast. The highest wind gust was 38 mph from the west on the 24th. May sunshine was close to average with 222.5 hours of bright sunshine, or 51 percent of possible, which was one percent less than the long-term average for the month.

BHO Warmest May Average Minimum Temperature, deg F (1885-2024):

1) 52.5 in 2012
2) 51.3 in 2018
3) 51.2 in 1944
4) 50.5 in 1979
   50.5 in 2022
6) 50.4 in 2010
7) 50.3 in 1991
8) 50.1 in 1998
9) 49.8 in 2011
   49.8 in 2024

BHO Lowest Seasonal (Oct-May) Snowfall, inches (1891-92 to 2023-24):

1) 12.6 in 1936-1937
2) 17.9 in 1994-1995
3) 23.1 in 1900-1901
4) 24.2 in 1972-1973
   24.2 in 2011-2012
6) 25.1 in 1918-1919
7) 25.3 in 1979-1980
8) 26.4 in 1985-1986
9) 26.8 in 2023-2024
10) 27.2 in 1991-1992

BHO Lowest May Mean Wind Speed, mph (1885-2024):

1) 10.0 in 2012
2) 10.3 in 2024
3) 10.8 in 2018
4) 11.1 in 2017
   11.1 in 2019
6) 11.2 in 1982
   11.2 in 2003

Mike Iacono
Chief Scientist
Blue Hill Observatory