September
September · May · October
77climate match
United States · 1991–2020
Best time to visit
New Haven.
September leads for comfortable weather in New Haven: typically 27.1°C by day, 13.9°C at night, with 85 mm of rain. Based on measured 1991–2020 NOAA station history.
Best comfortSeptember
Typical high27.1°C
Typical low13.9°C
Rain in September85 mm
August
August · July · June
74climate match
October
October · April · May
79climate match
The weakest month is January, scoring 5 against September’s 77 — days reach only 5.7°C, 18° below the 24°C the score treats as ideal.
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
55.7° / -4.8°
Feb
58.2° / -3.6°
Mar
2213.4° / 0.4°
Apr
5520.3° / 5.6°
May
7224.7° / 11.4°
Jun
6428.9° / 16.4°
Jul
5530.7° / 18.8°
Aug
6330.3° / 17.9°
Sep
7727.1° / 13.9°
Oct
6520.8° / 7.2°
Nov
3313.9° / 1.3°
Dec
58.1° / -2°
| Month | Day | Night | Rain | Wet days | Daylight | Comfort | Coverage |
|---|---|---|---|---|---|---|---|
| January | 5.7°C | -4.8°C | 78 mm | 9.9 | 9 h 42 | 5 | Strong coverage |
| February | 8.2°C | -3.6°C | 82 mm | 9.4 | 10 h 40 | 5 | Strong coverage |
| March | 13.4°C | 0.4°C | 104 mm | 10.4 | 11 h 50 | 22 | Strong coverage |
| April | 20.3°C | 5.6°C | 100 mm | 10.4 | 13 h 10 | 55 | Strong coverage |
| May | 24.7°C | 11.4°C | 119 mm | 11.1 | 14 h 17 | 72 | Strong coverage |
| June | 28.9°C | 16.4°C | 111 mm | 9.9 | 14 h 53 | 64 | Strong coverage |
| July | 30.7°C | 18.8°C | 110 mm | 9.3 | 14 h 39 | 55 | Strong coverage |
| August | 30.3°C | 17.9°C | 91 mm | 7.1 | 13 h 41 | 63 | Strong coverage |
| September | 27.1°C | 13.9°C | 85 mm | 7.3 | 12 h 24 | 77 | Strong coverage |
| October | 20.8°C | 7.2°C | 78 mm | 8.1 | 11 h 06 | 65 | Strong coverage |
| November | 13.9°C | 1.3°C | 71 mm | 8.2 | 9 h 59 | 33 | Strong coverage |
| December | 8.1°C | -2°C | 94 mm | 10.5 | 9 h 27 | 5 | Strong coverage |
What has changed
New Haven runs +0.1°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
0.0
Feb
+1.1
Mar
-0.5
Apr
-0.4
May
-0.4
Jun
-0.1
Jul
+0.3
Aug
0.0
Sep
+0.7
Oct
0.0
Nov
-0.6
Dec
+1.4
| Month | Record high | Record low | Wettest day | Wettest / driest month | Years |
|---|---|---|---|---|---|
| January | 26.1°C25 Jan 1950 | -33.3°C19 Jan 1994 | 62 mm22 Jan 1999 | 285 mm1937 · driest 11 mm in 2010 | 92 |
| February | 26.1°C25 Feb 2017 | -25.6°C4 Feb 1996 | 76 mm19 Feb 2000 | 186 mm1956 · driest 10 mm in 1941 | 92 |
| March | 31.1°C23 Mar 2026 | -22.8°C4 Mar 1943 | 65 mm2 Mar 1997 | 212 mm1997 · driest 30 mm in 1966 | 93 |
| April | 33.9°C3 Apr 2010 | -8.9°C1 Apr 1964 | 85 mm16 Apr 1939 | 242 mm1939 · driest 15 mm in 1976 | 92 |
| May | 36.7°C26 May 1939 | -5.0°C10 May 1966 | 99 mm3 May 2010 | 253 mm2003 · driest 12 mm in 1991 | 93 |
| June | 40.6°C17 Jun 1936 | 1.1°C11 Jun 1972 | 79 mm5 Jun 2008 | 260 mm1998 · driest 21 mm in 1984 | 93 |
| July | 45.0°C21 Jul 1934 | 6.1°C12 Jul 1945 | 120 mm22 Jul 1976 | 277 mm1980 · driest 11 mm in 1972 | 93 |
| August | 42.2°C21 Aug 1936 | 3.9°C29 Aug 1965 | 108 mm4 Aug 1963 | 287 mm1979 · driest 8 mm in 2012 | 91 |
| September | 40.6°C1 Sep 1953 | -2.8°C29 Sep 1942 | 102 mm18 Sep 2004 | 268 mm2004 · driest 1 mm in 2009 | 92 |
| October | 35.6°C8 Oct 2007 | -9.4°C27 Oct 1962 | 63 mm7 Oct 2019 | 180 mm2006 · driest 2 mm in 1963 | 92 |
| November | 31.7°C7 Nov 1938 | -17.8°C30 Nov 1958 | 58 mm4 Nov 1936 | 167 mm1986 · driest 7 mm in 1976 | 91 |
| December | 26.7°C2 Dec 1982 | -25.0°C21 Dec 1942 | 70 mm17 Dec 2019 | 213 mm1990 · driest 13 mm in 1965 | 91 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) | Snow days |
|---|---|---|---|---|---|
| January | 0 | 0 | 22 | 3 | 2 |
| February | <1 | 0 | 20 | 3 | 1 |
| March | 2 | <1 | 16 | 4 | <1 |
| April | 8 | <1 | 5 | 3 | 0 |
| May | 16 | 5 | <1 | 4 | 0 |
| June | 26 | 13 | 0 | 4 | 0 |
| July | 28 | 19 | 0 | 3 | 0 |
| August | 29 | 17 | 0 | 3 | 0 |
| September | 20 | 9 | 0 | 2 | 0 |
| October | 8 | 1 | 2 | 3 | 0 |
| November | 1 | 0 | 13 | 3 | <1 |
| December | 0 | 0 | 20 | 4 | <1 |
The best month has moved. On the 1961–1990 numbers the strongest month here was September (scoring 81); on 2011–2025 it is May (83). Both are scored the same way, from the same station — only the climate underneath changed.
| Month | Warm & dry days | Wet days | Washouts | Week with 3+ wet days | Daytime mean has ranged |
|---|---|---|---|---|---|
| January | 1% | 32% | 9% | 40% | 2.2–9.8°C |
| February | 3% | 32% | 9% | 42% | 4.4–11.3°C |
| March | 15% | 35% | 11% | 50% | 10.2–17.2°C |
| April | 38% | 34% | 10% | 45% | 17.5–22.9°C |
| May | 57% | 35% | 12% | 44% | 22.5–28.2°C |
| June | 67% | 32% | 11% | 41% | 27.2–31.5°C |
| July | 69% | 31% | 12% | 36% | 29.2–33.2°C |
| August | 75% | 26% | 10% | 26% | 28.4–32.6°C |
| September | 72% | 25% | 8% | 27% | 24.9–29.9°C |
| October | 50% | 25% | 7% | 26% | 19.3–23.7°C |
| November | 15% | 29% | 9% | 34% | 10.9–16.9°C |
| December | 2% | 31% | 9% | 40% | 4.2–10.9°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 4816522
- NOAA station
- USC00333029 · GALLIPOLIS
- Station distance
- 25.8 km from the place centre
- Climate period
- 1991–2020
- Minimum month coverage
- 29 usable years
- Daylight
- Calculated from latitude 38.99°, 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.