September
September · May · June
United States · 1991–2020
September leads for comfortable weather in Oakland: typically 25.5°C by day, 11.1°C at night, with 82 mm of rain. Based on measured 1991–2020 NOAA station history.
September · May · June
July · August · June
October · May · September
The weakest month is January, scoring 5 against September’s 79 — days reach only -0.4°C, 24° 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 | -0.4°C | -11.3°C | 17 mm | 3.4 | 9 h 27 | 5 | Strong coverage |
| February | 2.4°C | -8.9°C | 22 mm | 3.2 | 10 h 31 | 5 | Strong coverage |
| March | 9.7°C | -3.3°C | 46 mm | 5.3 | 11 h 48 | 16 | Strong coverage |
| April | 16.8°C | 3°C | 94 mm | 7.7 | 13 h 17 | 42 | Strong coverage |
| May | 22.6°C | 9.7°C | 109 mm | 9.1 | 14 h 31 | 70 | Strong coverage |
| June | 28°C | 15.6°C | 118 mm | 8.6 | 15 h 12 | 69 | Strong coverage |
| July | 30.2°C | 17.7°C | 78 mm | 7.3 | 14 h 56 | 65 | Strong coverage |
| August | 29.1°C | 16.5°C | 94 mm | 6.7 | 13 h 52 | 69 | Strong coverage |
| September | 25.5°C | 11.1°C | 82 mm | 6.2 | 12 h 26 | 79 | Strong coverage |
| October | 18.3°C | 4.2°C | 55 mm | 5.3 | 11 h 00 | 57 | Strong coverage |
| November | 9.1°C | -2.8°C | 37 mm | 4 | 9 h 46 | 18 | Strong coverage |
| December | 1.6°C | -8.4°C | 25 mm | 3.9 | 9 h 09 | 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 | 21.1°C10 Jan 1928 | -38.3°C12 Jan 1912 | 30 mm4 Jan 1949 | 68 mm1949 · driest 0 mm in 1987 | 126 |
| February | 25.6°C26 Feb 1896 | -36.1°C2 Feb 1905 | 36 mm13 Feb 1919 | 79 mm1971 · driest 0 mm in 2020 | 124 |
| March | 32.2°C30 Mar 1986 | -28.3°C5 Mar 1960 | 65 mm23 Mar 1987 | 173 mm1987 · driest 0 mm in 1910 | 125 |
| April | 37.8°C28 Apr 1910 | -15.0°C3 Apr 1936 | 93 mm30 Apr 2003 | 213 mm1999 · driest 8 mm in 2020 | 123 |
| May | 40.6°C31 May 1934 | -5.0°C4 May 1907 | 129 mm6 May 2007 | 286 mm2001 · driest 10 mm in 1933 | 124 |
| June | 42.8°C26 Jun 1936 | 1.7°C9 Jun 1903 | 168 mm11 Jun 1944 | 344 mm1944 · driest 2 mm in 1933 | 125 |
| July | 45.0°C25 Jul 1936 | 5.0°C6 Jul 1895 | 120 mm14 Jul 1929 | 288 mm1902 · driest 0 mm in 2012 | 125 |
| August | 43.3°C8 Aug 1934 | 3.9°C30 Aug 1915 | 210 mm7 Aug 1999 | 233 mm1999 · driest 11 mm in 1973 | 123 |
| September | 41.7°C6 Sep 1939 | -5.0°C30 Sep 1899 | 97 mm6 Sep 1938 | 258 mm1901 · driest 4 mm in 1980 | 127 |
| October | 36.1°C3 Oct 1938 | -18.3°C30 Oct 1925 | 121 mm12 Oct 1928 | 178 mm1984 · driest 0 mm in 1988 | 126 |
| November | 30.0°C18 Nov 1908 | -23.9°C29 Nov 1976 | 57 mm4 Nov 1922 | 128 mm1922 · driest 0 mm in 2021 | 125 |
| December | 21.1°C16 Dec 2021 | -32.2°C23 Dec 1989 | 69 mm14 Dec 2015 | 110 mm2015 · driest 0 mm in 1982 | 125 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) | Snow days |
|---|---|---|---|---|---|
| January | 0 | 0 | 29 | <1 | 3 |
| February | 0 | 0 | 27 | <1 | 3 |
| March | 1 | 0 | 23 | 2 | 2 |
| April | 4 | 1 | 9 | 3 | <1 |
| May | 12 | 4 | <1 | 4 | 0 |
| June | 24 | 12 | 0 | 4 | 0 |
| July | 29 | 17 | 0 | 3 | 0 |
| August | 27 | 13 | 0 | 3 | 0 |
| September | 18 | 7 | <1 | 2 | 0 |
| October | 6 | 1 | 7 | 2 | <1 |
| November | <1 | 0 | 21 | 1 | 1 |
| December | 0 | 0 | 29 | <1 | 3 |
| Month | Warm & dry days | Wet days | Washouts | Week with 3+ wet days | Daytime mean has ranged |
|---|---|---|---|---|---|
| January | <1% | 12% | 2% | 6% | -4.6–4.7°C |
| February | <1% | 13% | 3% | 7% | -2.6–6.6°C |
| March | 11% | 18% | 5% | 15% | 4.3–13.5°C |
| April | 32% | 26% | 9% | 30% | 13.9–20.8°C |
| May | 54% | 31% | 11% | 37% | 20.5–26.6°C |
| June | 67% | 31% | 12% | 35% | 26.2–31.6°C |
| July | 76% | 25% | 9% | 24% | 29.2–34.0°C |
| August | 76% | 24% | 10% | 22% | 28.0–32.6°C |
| September | 70% | 22% | 9% | 21% | 23.3–28.8°C |
| October | 45% | 17% | 5% | 14% | 16.3–22.5°C |
| November | 8% | 13% | 4% | 8% | 6.3–12.7°C |
| December | <1% | 12% | 2% | 7% | -2.3–5.6°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