September
September · May · June
United States · 1991–2020
September leads for comfortable weather in Princeton Junction: typically 25.7°C by day, 12.6°C at night, with 104 mm of rain. Based on measured 1991–2020 NOAA station history.
September · May · June
August · July · June
October · May · April
The weakest month is January, scoring 5 against September’s 77 — days reach only 4.7°C, 19° below the 24°C the score treats as ideal.
Month by month
The bars show the comfort score. Day and night temperatures come from daily observed highs and lows; rain is the historical monthly estimate.
| Month | Day | Night | Rain | Wet days | Daylight | Comfort | Coverage |
|---|---|---|---|---|---|---|---|
| January | 4.7°C | -5.3°C | 88 mm | 8.8 | 9 h 35 | 5 | Strong coverage |
| February | 6.1°C | -4.5°C | 68 mm | 7.7 | 10 h 36 | 5 | Strong coverage |
| March | 10.5°C | -0.7°C | 108 mm | 9.2 | 11 h 49 | 11 | Strong coverage |
| April | 17.2°C | 4.5°C | 94 mm | 9.1 | 13 h 13 | 45 | Strong coverage |
| May | 22.6°C | 9.7°C | 104 mm | 10 | 14 h 23 | 70 | Strong coverage |
| June | 27.6°C | 14.9°C | 118 mm | 9.5 | 15 h 02 | 70 | Strong coverage |
| July | 30.4°C | 17.8°C | 123 mm | 8.9 | 14 h 47 | 56 | Strong coverage |
| August | 29.4°C | 16.5°C | 112 mm | 8.5 | 13 h 46 | 64 | Strong coverage |
| September | 25.7°C | 12.6°C | 104 mm | 7.2 | 12 h 24 | 77 | Strong coverage |
| October | 19.1°C | 6.3°C | 101 mm | 7.9 | 11 h 04 | 54 | Strong coverage |
| November | 13°C | 1.2°C | 82 mm | 7.2 | 9 h 53 | 28 | Strong coverage |
| December | 7.5°C | -2.4°C | 107 mm | 8.9 | 9 h 19 | 5 | Strong coverage |
What has changed
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.
| Month | Record high | Record low | Wettest day | Wettest / driest month | Years |
|---|---|---|---|---|---|
| January | 22.8°C14 Jan 1932 | -26.7°C28 Jan 1935 | 69 mm13 Jan 1915 | 220 mm1979 · driest 9 mm in 1981 | 128 |
| February | 25.0°C22 Feb 2018 | -23.9°C7 Feb 1907 | 77 mm6 Feb 1896 | 193 mm2018 · driest 15 mm in 2009 | 129 |
| March | 31.1°C31 Mar 1998 | -16.7°C19 Mar 1967 | 65 mm13 Mar 1953 | 229 mm2010 · driest 16 mm in 1910 | 131 |
| April | 35.0°C18 Apr 2002 | -12.2°C1 Apr 1923 | 139 mm16 Apr 2007 | 290 mm2007 · driest 21 mm in 1963 | 132 |
| May | 36.1°C27 May 1914 | -2.2°C1 May 1978 | 104 mm1 May 2014 | 248 mm2018 · driest 14 mm in 1964 | 132 |
| June | 37.8°C25 Jun 2025 | 1.7°C1 Jun 1938 | 135 mm27 Jun 1938 | 271 mm2013 · driest 1 mm in 1949 | 131 |
| July | 40.6°C9 Jul 1936 | 5.6°C3 Jul 1929 | 141 mm6 Jul 1989 | 310 mm1897 · driest 3 mm in 1955 | 128 |
| August | 38.9°C10 Aug 2001 | 4.4°C30 Aug 1986 | 200 mm28 Aug 2011 | 490 mm2011 · driest 7 mm in 1964 | 130 |
| September | 39.4°C2 Sep 1953 | -0.6°C25 Sep 1963 | 142 mm17 Sep 1999 | 297 mm1975 · driest 1 mm in 1941 | 129 |
| October | 35.0°C5 Oct 1941 | -5.6°C21 Oct 1930 | 151 mm9 Oct 1903 | 304 mm2005 · driest 0 mm in 2024 | 132 |
| November | 28.3°C1 Nov 2024 | -17.8°C26 Nov 1938 | 101 mm15 Nov 1892 | 241 mm2018 · driest 9 mm in 1976 | 132 |
| December | 24.4°C8 Dec 1998 | -24.4°C30 Dec 1917 | 81 mm18 Dec 2023 | 225 mm2023 · driest 3 mm in 1955 | 131 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) | Snow days |
|---|---|---|---|---|---|
| January | 0 | 0 | 26 | 3 | 3 |
| February | 0 | 0 | 24 | 2 | 3 |
| March | <1 | 0 | 19 | 4 | 2 |
| April | 4 | <1 | 5 | 3 | <1 |
| May | 11 | 4 | <1 | 3 | 0 |
| June | 22 | 10 | 0 | 4 | 0 |
| July | 29 | 19 | 0 | 4 | 0 |
| August | 28 | 15 | 0 | 3 | 0 |
| September | 18 | 5 | 0 | 3 | 0 |
| October | 4 | <1 | 3 | 3 | 0 |
| November | <1 | 0 | 14 | 3 | <1 |
| December | 0 | 0 | 23 | 4 | 2 |
| Month | Warm & dry days | Wet days | Washouts | Week with 3+ wet days | Daytime mean has ranged |
|---|---|---|---|---|---|
| January | <1% | 28% | 10% | 28% | 0.5–7.5°C |
| February | <1% | 28% | 10% | 30% | 1.9–8.8°C |
| March | 7% | 30% | 12% | 34% | 7.4–13.5°C |
| April | 23% | 30% | 11% | 36% | 14.9–19.1°C |
| May | 54% | 30% | 10% | 38% | 20.6–24.9°C |
| June | 68% | 30% | 11% | 32% | 25.6–29.2°C |
| July | 71% | 29% | 13% | 32% | 28.3–31.8°C |
| August | 71% | 28% | 12% | 28% | 27.1–30.6°C |
| September | 70% | 23% | 10% | 21% | 23.5–27.2°C |
| October | 37% | 22% | 9% | 20% | 17.2–21.4°C |
| November | 7% | 25% | 10% | 24% | 10.2–15.2°C |
| December | <1% | 26% | 11% | 27% | 3.1–9.3°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