September
September · May · October
77climate match
United States · 1991–2020
Best time to visit
Hanover.
September leads for comfortable weather in Hanover: typically 27.7°C by day, 13.4°C at night, with 76 mm of rain. Based on measured 1991–2020 NOAA station history.
Best comfortSeptember
Typical high27.7°C
Typical low13.4°C
Rain in September76 mm
August
August · July · June
70climate match
October
October · April · May
84climate match
The weakest month is January, scoring 5 against September’s 77 — days reach only 3.7°C, 20° below the 24°C the score treats as ideal, and nights drop to -8.4°C.
Month by month
The whole year,
without the guesswork.
The bars show the comfort score. Day and night temperatures come from daily observed highs and lows; rain is the historical monthly estimate.
Jan
53.7° / -8.4°
Feb
56.6° / -6.4°
Mar
3313.5° / -0.8°
Apr
5619.3° / 5°
May
7524.6° / 11.4°
Jun
5930.2° / 17.2°
Jul
4833° / 19.9°
Aug
5631.7° / 18.5°
Sep
7727.7° / 13.4°
Oct
6820.7° / 6.2°
Nov
3012° / -1.1°
Dec
55.3° / -6.3°
| Month | Day | Night | Rain | Wet days | Daylight | Comfort | Coverage |
|---|---|---|---|---|---|---|---|
| January | 3.7°C | -8.4°C | 20 mm | 3.4 | 9 h 38 | 5 | Strong coverage |
| February | 6.6°C | -6.4°C | 31 mm | 3.8 | 10 h 37 | 5 | Strong coverage |
| March | 13.5°C | -0.8°C | 47 mm | 5.2 | 11 h 49 | 33 | Strong coverage |
| April | 19.3°C | 5°C | 84 mm | 7.3 | 13 h 12 | 56 | Strong coverage |
| May | 24.6°C | 11.4°C | 113 mm | 9.1 | 14 h 21 | 75 | Strong coverage |
| June | 30.2°C | 17.2°C | 121 mm | 8.3 | 14 h 59 | 59 | Strong coverage |
| July | 33°C | 19.9°C | 105 mm | 7.2 | 14 h 44 | 48 | Strong coverage |
| August | 31.7°C | 18.5°C | 94 mm | 7 | 13 h 44 | 56 | Strong coverage |
| September | 27.7°C | 13.4°C | 76 mm | 5.8 | 12 h 24 | 77 | Strong coverage |
| October | 20.7°C | 6.2°C | 59 mm | 5.7 | 11 h 05 | 68 | Strong coverage |
| November | 12°C | -1.1°C | 39 mm | 4.4 | 9 h 55 | 30 | Strong coverage |
| December | 5.3°C | -6.3°C | 31 mm | 3.7 | 9 h 21 | 5 | Strong coverage |
What has changed
Hanover runs -0.4°C
on the 1961–1990 baseline.
Each bar compares the 2011–2025 daytime average for that month against the same month in 1961–1990, measured at the same station. Months where the older record is too thin to compare are left blank.
Jan
-0.5
Feb
-1.5
Mar
+0.3
Apr
-1.5
May
-1.1
Jun
+0.3
Jul
-1.1
Aug
-1.2
Sep
+1.1
Oct
-0.7
Nov
+0.3
Dec
+1.0
| Month | Record high | Record low | Wettest day | Wettest / driest month | Years |
|---|---|---|---|---|---|
| January | 23.9°C10 Jan 1990 | -31.1°C4 Jan 1959 | 30 mm16 Jan 2017 | 57 mm1993 · driest 0 mm in 1986 | 74 |
| February | 29.4°C29 Feb 1972 | -33.9°C16 Feb 2021 | 42 mm9 Feb 2001 | 142 mm2001 · driest 0 mm in 1963 | 75 |
| March | 35.0°C22 Mar 2026 | -27.8°C4 Mar 1978 | 74 mm31 Mar 2007 | 205 mm1987 · driest 0 mm in 1966 | 76 |
| April | 36.7°C26 Apr 1989 | -15.0°C3 Apr 1975 | 163 mm13 Apr 1991 | 192 mm1991 · driest 7 mm in 1989 | 77 |
| May | 39.4°C25 May 1967 | -2.2°C2 May 1967 | 84 mm12 May 2005 | 254 mm1995 · driest 18 mm in 2012 | 77 |
| June | 41.7°C27 Jun 1980 | 4.4°C1 Jun 1983 | 110 mm18 Jun 1983 | 310 mm1967 · driest 17 mm in 2016 | 76 |
| July | 44.4°C12 Jul 1954 | 6.7°C30 Jul 1971 | 91 mm25 Jul 1992 | 511 mm1993 · driest 0 mm in 2003 | 76 |
| August | 43.3°C11 Aug 1894 | 6.1°C31 Aug 1955 | 134 mm25 Aug 1972 | 325 mm1954 · driest 0 mm in 1971 | 75 |
| September | 41.7°C2 Sep 2000 | -3.3°C29 Sep 1984 | 127 mm1 Sep 2025 | 288 mm1973 · driest 3 mm in 1956 | 75 |
| October | 36.1°C4 Oct 1963 | -10.6°C31 Oct 1993 | 99 mm11 Oct 1973 | 160 mm2007 · driest 0 mm in 1952 | 75 |
| November | 28.9°C9 Nov 2006 | -21.1°C28 Nov 1976 | 65 mm12 Nov 2010 | 141 mm1998 · driest 0 mm in 1954 | 76 |
| December | 22.8°C3 Dec 2021 | -33.9°C23 Dec 1989 | 57 mm13 Dec 2015 | 114 mm2015 · driest 0 mm in 1977 | 75 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) | Snow days |
|---|---|---|---|---|---|
| January | 0 | 0 | 29 | <1 | 3 |
| February | <1 | 0 | 24 | 1 | 3 |
| March | 2 | <1 | 18 | 1 | 1 |
| April | 7 | 2 | 6 | 3 | <1 |
| May | 16 | 6 | <1 | 4 | 0 |
| June | 26 | 17 | 0 | 4 | 0 |
| July | 30 | 25 | 0 | 3 | 0 |
| August | 29 | 21 | 0 | 3 | 0 |
| September | 22 | 11 | <1 | 2 | 0 |
| October | 9 | 2 | 5 | 2 | <1 |
| November | <1 | 0 | 18 | 1 | <1 |
| December | 0 | 0 | 28 | 1 | 2 |
| Month | Warm & dry days | Wet days | Washouts | Week with 3+ wet days | Daytime mean has ranged |
|---|---|---|---|---|---|
| January | <1% | 10% | 2% | 6% | -0.1–8.0°C |
| February | 5% | 12% | 3% | 7% | 1.4–11.9°C |
| March | 22% | 17% | 5% | 14% | 8.5–17.3°C |
| April | 45% | 23% | 8% | 24% | 16.9–22.2°C |
| May | 62% | 28% | 13% | 33% | 22.7–27.8°C |
| June | 73% | 27% | 12% | 31% | 28.4–32.5°C |
| July | 77% | 24% | 10% | 24% | 30.9–35.9°C |
| August | 78% | 22% | 10% | 21% | 30.1–34.6°C |
| September | 76% | 20% | 9% | 17% | 25.5–30.5°C |
| October | 57% | 16% | 6% | 14% | 18.6–23.9°C |
| November | 14% | 13% | 4% | 7% | 8.9–15.4°C |
| December | <1% | 10% | 3% | 5% | 2.0–9.3°C |
A warm and dry day reaches 20°C with under 1 mm of rain; a wet day gets 1 mm or more; a washout gets 10 mm or more. The week column is the share of seven-day stretches in that month, across the station’s whole daily record, that contained three or more wet days — the odds a week-long trip is rained on repeatedly, counted rather than modelled. The last column is the 10th to 90th percentile of that month’s daytime average across individual years: a narrow band means the average is what you will get, a wide one means the average is a midpoint between years that felt quite different.
The evidence behind this page
Nearby, measured,
and named.
- Place identity
- GeoNames 4272600
- NOAA station
- USC00148578 · WASHINGTON
- Station distance
- 17.7 km from the place centre
- Climate period
- 1991–2020
- Minimum month coverage
- 29 usable years
- Daylight
- Calculated from latitude 39.89°, mid-month, sunrise to sunset including refraction. Not a station measurement.
- Important limit
- Historical climate is not a forecast. Nearby stations can miss mountains, coasts, and local microclimates.