July 2025 Summary – Tenth Warmest on Record

Blue Hill Observatory July 2025 Summary: 

July 2025 was much warmer and wetter than average with above average sunshine. The approximated 24-hour mean temperature for the month of 73.9 deg F was 3.9 degrees warmer than the 1891-2020 130-year average for July, and it was 2.2 degrees warmer than the 1991-2020 30-year average. The month was the tenth warmest July on record. The average maximum temperature of 84.5 deg F was 2.8 degrees warmer than the 30-year normal, which tied as the eighth warmest on record. The average minimum temperature of 65.1 deg F was 1.3 degrees warmer than the 30-year normal, which tied as the tenth warmest on record. Eighteen days during the month were warmer than normal, including eight days that reached or exceeded ninety degrees, which was five more than average. The highest temperature for the month was 96F on July 29th, and the lowest temperature was 55F on the 22nd. July mean water vapor pressure, which is an absolute measure of water vapor in the air, was 21.8 mb, which corresponded to a mean dew point of about 66F. This amount was well above the long-term mean water vapor pressure for July of 18.9 mb, which equals a mean dew point of about 62F. The total precipitation was 6.22 inches, which was 2.75 inches more than the 30-year normal. The greatest amount in 24 hours was 3.85 inches on the 10th, which was caused by an exceptionally heavy band of rain including a thunderstorm that morning. On that day, 1.35 inches of rain was recorded in a single hour from 5-6 AM EST, and 2.46 inches was measured over two hours from 5-7 AM EST. Another 1.09 inches of rain was recorded during several hours of thunderstorms on the night of the 8th-9th. There were eight thunderstorm days during the month, which was three more than average, and the total for the year through July increased to 16. The mean wind speed was 9.9 mph, and the prevailing wind direction was from the south-southwest. The highest wind gust was 41 mph from the west-northwest on the 17th. July sunshine was above average with 277.7 hours of bright sunshine, or 62 percent of possible, which was four percent more than the long-term average for the month.

BHO Warmest July Approximated 24-Hour Mean Temperature, deg F (1885-2025):

1) 75.3 in 2022
2) 75.1 in 2010
3) 74.9 in 1952
4) 74.5 in 2019
5) 74.1 in 1994
   74.1 in 2013
7) 74.0 in 2011
   74.0 in 2016
   74.0 in 2024
10) 73.9 in 2025

BHO Warmest July Average Maximum Temperature, deg F (1885-2025):

1) 87.2 in 1952
2) 86.6 in 2022
3) 86.5 in 2010
4) 85.5 in 1949
5) 84.9 in 1994
6) 84.7 in 2016
7) 84.6 in 2019
8) 84.5 in 1911
   84.5 in 2025
10) 84.4 in 1983

BHO Warmest July Average Minimum Temperature, deg F (1885-2025):

1) 66.9 in 2013
2) 66.7 in 2024
3) 66.0 in 2020
4) 65.9 in 2010
5) 65.7 in 2022
   65.7 in 2023
7) 65.6 in 1994
   65.6 in 2019
9) 65.3 in 2006
10) 65.1 in 2008
   65.1 in 2025

BHO Highest July Mean Water Vapor Pressure, mb (1932-2025):

1) 23.5 in 2013
2) 22.9 in 2023
3) 22.5 in 1994
4) 22.2 in 2024
5) 21.8 in 2020
   21.8 in 2025
7) 21.7 in 2006

Mike Iacono
Chief Scientist
Blue Hill Observatory