September weather in Portsmouth, NH
The average temperature in Portsmouth in September is °F (°F–°F). Average precipitation: 4.00 inches.
September is a fall month in Portsmouth, and is cooler than the annual average of 0°F. Expect about 8 days with precipitation. Daylight averages about 12h 17m.
Avg High
°F
Avg Low
°F
Precipitation
4.00 in
Daylight
12h 17m
September records in Portsmouth
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| September 1 | — | — | 0.77 in (2001) |
| September 2 | — | — | 2.72 in (2021) |
| September 3 | — | — | 1.91 in (2013) |
| September 4 | — | — | 1.16 in (2017) |
| September 5 | — | — | 1.66 in (2022) |
| September 6 | — | — | 0.73 in (2022) |
| September 7 | — | — | 5.85 in (2008) |
| September 8 | — | — | 1.12 in (2011) |
| September 9 | — | — | 2.08 in (2004) |
| September 10 | — | — | 1.05 in (2004) |
| September 11 | — | — | 3.65 in (1999) |
| September 12 | — | — | 1.76 in (2007) |
| September 13 | — | — | 2.00 in (2013) |
| September 14 | — | — | 1.20 in (2013) |
| September 15 | — | — | 0.29 in (2006) |
| September 16 | — | — | 1.10 in (2000) |
| September 17 | — | — | 3.21 in (1999) |
| September 18 | — | — | 1.18 in (1995) |
| September 19 | — | — | 3.08 in (2023) |
| September 20 | — | — | 1.30 in (2006) |
| September 21 | — | — | 0.50 in (1997) |
| September 22 | — | — | 0.76 in (2013) |
| September 23 | — | — | 1.50 in (2022) |
| September 24 | — | — | 1.29 in (2003) |
| September 25 | — | — | 0.54 in (2006) |
| September 26 | — | — | 1.16 in (2025) |
| September 27 | — | — | 4.13 in (2008) |
| September 28 | — | — | 1.98 in (1993) |
| September 29 | — | — | 1.07 in (2012) |
| September 30 | — | — | 1.29 in (2011) |