September
September · August · June
82climate match
United States · 1991–2020
Best time to visit
Greenwich.
September leads for comfortable weather in Greenwich: typically 23.6°C by day, 12°C at night, with 85 mm of rain. Based on measured 1991–2020 NOAA station history.
Best comfortSeptember
Typical high23.6°C
Typical low12°C
Rain in September85 mm
July
July · August · June
68climate match
May
May · September · October
72climate match
The weakest month is January, scoring 5 against September’s 82 — days reach only 0.9°C, 23° 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
50.9° / -7.2°
Feb
52.5° / -6.1°
Mar
58° / -1.9°
Apr
3415.5° / 3.7°
May
6421.5° / 9.7°
Jun
7426.1° / 14.7°
Jul
7028° / 16.7°
Aug
7627.1° / 15.9°
Sep
8223.6° / 12°
Oct
4916.9° / 6.1°
Nov
159.5° / 0.7°
Dec
53.4° / -4°
| Month | Day | Night | Rain | Wet days | Daylight | Comfort | Coverage |
|---|---|---|---|---|---|---|---|
| January | 0.9°C | -7.2°C | 82 mm | 11.4 | 9 h 31 | 5 | Strong coverage |
| February | 2.5°C | -6.1°C | 64 mm | 9.6 | 10 h 34 | 5 | Strong coverage |
| March | 8°C | -1.9°C | 85 mm | 10.6 | 11 h 49 | 5 | Strong coverage |
| April | 15.5°C | 3.7°C | 108 mm | 11.5 | 13 h 15 | 34 | Strong coverage |
| May | 21.5°C | 9.7°C | 106 mm | 11.7 | 14 h 27 | 64 | Strong coverage |
| June | 26.1°C | 14.7°C | 122 mm | 10.4 | 15 h 06 | 74 | Strong coverage |
| July | 28°C | 16.7°C | 98 mm | 8.6 | 14 h 51 | 70 | Strong coverage |
| August | 27.1°C | 15.9°C | 92 mm | 8 | 13 h 49 | 76 | Strong coverage |
| September | 23.6°C | 12°C | 85 mm | 7.7 | 12 h 25 | 82 | Strong coverage |
| October | 16.9°C | 6.1°C | 80 mm | 8.7 | 11 h 02 | 49 | Strong coverage |
| November | 9.5°C | 0.7°C | 80 mm | 9.1 | 9 h 50 | 15 | Strong coverage |
| December | 3.4°C | -4°C | 77 mm | 10.3 | 9 h 14 | 5 | Strong coverage |
What has changed
Greenwich runs +1.3°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
+1.3
Feb
+1.8
Mar
+1.4
Apr
+1.2
May
+1.6
Jun
+1.2
Jul
+0.9
Aug
+0.9
Sep
+1.6
Oct
+1.1
Nov
+0.4
Dec
+2.5
| Month | Record high | Record low | Wettest day | Wettest / driest month | Years |
|---|---|---|---|---|---|
| January | 20.6°C25 Jan 1950 | -30.0°C19 Jan 1994 | 68 mm15 Jan 1950 | 291 mm1950 · driest 10 mm in 1981 | 75 |
| February | 23.3°C24 Feb 2017 | -23.9°C17 Feb 1979 | 70 mm25 Feb 1961 | 154 mm2008 · driest 7 mm in 1978 | 75 |
| March | 28.9°C22 Mar 2012 | -21.1°C2 Mar 1980 | 61 mm4 Mar 1964 | 179 mm1964 · driest 30 mm in 1960 | 75 |
| April | 30.0°C27 Apr 1986 | -13.3°C7 Apr 1982 | 68 mm23 Apr 1996 | 221 mm1996 · driest 19 mm in 1971 | 75 |
| May | 33.3°C18 May 1962 | -3.9°C10 May 1966 | 69 mm9 May 2021 | 224 mm1989 · driest 27 mm in 1954 | 75 |
| June | 38.3°C25 Jun 1988 | 2.8°C5 Jun 1990 | 95 mm18 Jun 1978 | 254 mm1981 · driest 14 mm in 1988 | 75 |
| July | 37.8°C7 Jul 1988 | 6.1°C1 Jul 1988 | 86 mm11 Jul 1990 | 336 mm1992 · driest 24 mm in 1975 | 74 |
| August | 36.1°C17 Aug 1988 | 4.4°C29 Aug 1965 | 110 mm21 Aug 2007 | 262 mm2007 · driest 16 mm in 1970 | 73 |
| September | 36.1°C3 Sep 1953 | 0.6°C23 Sep 1995 | 81 mm7 Sep 2020 | 197 mm1986 · driest 15 mm in 2023 | 73 |
| October | 32.2°C1 Oct 2019 | -6.7°C30 Oct 1988 | 85 mm5 Oct 1995 | 185 mm2012 · driest 9 mm in 2024 | 73 |
| November | 26.1°C1 Nov 2016 | -16.7°C30 Nov 1976 | 79 mm14 Nov 1993 | 326 mm1985 · driest 18 mm in 1976 | 73 |
| December | 22.8°C3 Dec 1982 | -27.2°C22 Dec 1989 | 67 mm3 Dec 1990 | 284 mm1990 · driest 7 mm in 1955 | 75 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) | Snow days |
|---|---|---|---|---|---|
| January | 0 | 0 | 27 | 2 | 11 |
| February | 0 | 0 | 24 | 2 | 9 |
| March | <1 | 0 | 21 | 3 | 6 |
| April | 2 | 0 | 8 | 4 | 2 |
| May | 10 | 2 | <1 | 4 | 0 |
| June | 20 | 6 | 0 | 5 | 0 |
| July | 26 | 10 | 0 | 3 | 0 |
| August | 24 | 7 | 0 | 3 | 0 |
| September | 12 | 3 | 0 | 3 | 0 |
| October | 3 | <1 | 4 | 3 | <1 |
| November | <1 | 0 | 15 | 2 | 3 |
| December | 0 | 0 | 25 | 3 | 8 |
| Month | Warm & dry days | Wet days | Washouts | Week with 3+ wet days | Daytime mean has ranged |
|---|---|---|---|---|---|
| January | 0% | 33% | 6% | 43% | -2.9–4.5°C |
| February | <1% | 32% | 6% | 42% | -1.1–5.7°C |
| March | 5% | 35% | 9% | 49% | 4.9–11.3°C |
| April | 17% | 37% | 11% | 50% | 12.6–17.4°C |
| May | 40% | 36% | 12% | 49% | 18.3–24.0°C |
| June | 64% | 31% | 13% | 37% | 24.3–27.8°C |
| July | 73% | 27% | 10% | 27% | 26.2–29.8°C |
| August | 72% | 27% | 10% | 27% | 25.1–28.7°C |
| September | 61% | 25% | 9% | 26% | 21.0–25.8°C |
| October | 27% | 26% | 7% | 29% | 14.5–19.6°C |
| November | 5% | 31% | 8% | 39% | 6.3–12.1°C |
| December | <1% | 33% | 8% | 43% | -1.0–6.6°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 5156513
- NOAA station
- USW00014891 · MANSFIELD LAHM RGNL AP
- Station distance
- 23.3 km from the place centre
- Climate period
- 1991–2020
- Minimum month coverage
- 30 usable years
- Daylight
- Calculated from latitude 41.03°, 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.