Acton Weather in September
Average highs run from 78°F on September 1 to 67°F on September 30, and lows from 52°F to 41°F. Normal precipitation for the month is 3.82 in over about 9 wet days.
September day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
September at a glance
- Average high
- 73°F
- Average low
- 47°F
- Precipitation
- 3.82 in
- Record high
- 95°FSep 2, 1953
- Record low
- 22°FSep 30, 2018
- Chance of a freeze
- 52%
- Days of 90°F or more
- 0.6
- Daylight
- 13 h 11 min to 11 h 46 min
- Cloud cover
- 54%
- Humidity
- 79%
- Dew point
- 53°F
- Wind
- 4.3 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.
| Date | Normal high | Normal low | Record high | Record low | Chance wet | Chance of snow |
|---|---|---|---|---|---|---|
| Sep 1 | 78°F | 52°F | 91°F 1969 | 38°F 1970 | 28% | 0% |
| Sep 2 | 78°F | 52°F | 95°F 1953 | 38°F 1964 | 28% | 0% |
| Sep 3 | 77°F | 51°F | 92°F 1953 | 38°F 1958 | 28% | 0% |
| Sep 4 | 77°F | 51°F | 91°F 2018 | 36°F 1987 | 28% | 0% |
| Sep 5 | 77°F | 51°F | 90°F 1961 | 34°F 1965 | 28% | 0% |
| Sep 6 | 76°F | 51°F | 91°F 2018 | 35°F 1960 | 28% | 0% |
| Sep 7 | 76°F | 50°F | 90°F 2023 | 34°F 1962 | 28% | 0% |
| Sep 8 | 76°F | 50°F | 95°F 1960 | 33°F 1955 | 29% | 0% |
| Sep 9 | 75°F | 50°F | 94°F 2002 | 37°F 1984 | 29% | 0% |
| Sep 10 | 75°F | 49°F | 94°F 2002 | 34°F 1956 | 29% | 0% |
| Sep 11 | 75°F | 49°F | 94°F 1983 | 35°F 1953 | 29% | 0% |
| Sep 12 | 74°F | 49°F | 92°F 2013 | 31°F 1965 | 29% | 0% |
| Sep 13 | 74°F | 48°F | 88°F 1961 | 34°F 1954 | 29% | 0% |
| Sep 14 | 74°F | 48°F | 87°F 1961 | 28°F 1963 | 29% | 0% |
| Sep 15 | 73°F | 47°F | 89°F 1993 | 27°F 1963 | 30% | 0% |
| Sep 16 | 73°F | 47°F | 89°F 1957 | 26°F 1964 | 30% | 0% |
| Sep 17 | 72°F | 47°F | 86°F 1991 | 29°F 1959 | 30% | 0% |
| Sep 18 | 72°F | 46°F | 90°F 1955 | 31°F 1959 | 30% | 0% |
| Sep 19 | 72°F | 46°F | 89°F 1955 | 29°F 1956 | 30% | 0% |
| Sep 20 | 71°F | 45°F | 91°F 1983 | 24°F 1964 | 30% | 0% |
| Sep 21 | 71°F | 45°F | 90°F 1978 | 26°F 1964 | 30% | 0% |
| Sep 22 | 70°F | 45°F | 89°F 1978 | 24°F 1962 | 31% | 0% |
| Sep 23 | 70°F | 44°F | 89°F 1965 | 25°F 2018 | 31% | 0% |
| Sep 24 | 70°F | 44°F | 87°F 2019 | 25°F 2018 | 31% | 0% |
| Sep 25 | 69°F | 43°F | 89°F 2017 | 28°F 1974 | 31% | 0% |
| Sep 26 | 69°F | 43°F | 88°F 2007 | 26°F 1966 | 32% | 0% |
| Sep 27 | 68°F | 43°F | 88°F 2017 | 28°F 1955 | 32% | 0% |
| Sep 28 | 68°F | 42°F | 88°F 2017 | 23°F 1965 | 32% | 0% |
| Sep 29 | 67°F | 42°F | 85°F 2014 | 24°F 2018 | 32% | 0% |
| Sep 30 | 67°F | 41°F | 85°F 1986 | 22°F 2018 | 32% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (EDT).
- September 1
- sunrise 6:08 AM, sunset 7:19 PM
- September 30
- sunrise 6:40 AM, sunset 6:26 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00177479 (Sanford 2 Nnw), public domain. Records: NOAA GHCN-Daily, station USC00177479, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.