September
September · May · August
United States · 1991–2020
September leads for comfortable weather in Amazonia: typically 26.9°C by day, 13°C at night, with 75 mm of rain. Based on measured 1991–2020 NOAA station history.
September · May · August
July · August · June
October · April · September
The weakest month is January, scoring 5 against September’s 78 — days reach only 3.4°C, 21° below the 24°C the score treats as ideal, and nights drop to -8.1°C.
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 | 3.4°C | -8.1°C | 17 mm | 3.1 | 9 h 38 | 5 | Good coverage |
| February | 5.7°C | -6.1°C | 27 mm | 3.9 | 10 h 37 | 5 | Good coverage |
| March | 12.8°C | -0.1°C | 49 mm | 6.2 | 11 h 49 | 31 | Good coverage |
| April | 19°C | 5.7°C | 93 mm | 8.5 | 13 h 12 | 54 | Good coverage |
| May | 24.6°C | 12.1°C | 117 mm | 9.3 | 14 h 21 | 76 | Good coverage |
| June | 29.4°C | 17.7°C | 122 mm | 9.3 | 14 h 59 | 59 | Good coverage |
| July | 31.2°C | 19.7°C | 94 mm | 6.2 | 14 h 44 | 57 | Good coverage |
| August | 30.3°C | 18°C | 98 mm | 6.8 | 13 h 44 | 62 | Good coverage |
| September | 26.9°C | 13°C | 75 mm | 6 | 12 h 24 | 78 | Good coverage |
| October | 19.8°C | 6°C | 80 mm | 6.3 | 11 h 05 | 61 | Strong coverage |
| November | 12.3°C | -0.5°C | 39 mm | 4.2 | 9 h 55 | 32 | Strong coverage |
| December | 5°C | -6.3°C | 30 mm | 3.6 | 9 h 21 | 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°C8 Jan 2003 | -31.7°C12 Jan 1974 | 63 mm1 Jan 1965 | 116 mm1949 · driest 0 mm in 2009 | 56 |
| February | 26.7°C26 Feb 2024 | -30.6°C1 Feb 1979 | 40 mm27 Feb 2023 | 89 mm2023 · driest 0 mm in 2022 | 56 |
| March | 35.0°C21 Mar 2026 | -25.0°C4 Mar 1978 | 61 mm4 Mar 1976 | 186 mm1973 · driest 7 mm in 1970 | 56 |
| April | 35.6°C28 Apr 1970 | -16.7°C3 Apr 1975 | 78 mm26 Apr 2016 | 171 mm1999 · driest 14 mm in 2018 | 56 |
| May | 38.9°C26 May 2018 | -1.7°C3 May 2005 | 118 mm17 May 1974 | 248 mm2015 · driest 34 mm in 1966 | 56 |
| June | 40.6°C27 Jun 1980 | 5.6°C1 Jun 1979 | 107 mm24 Jun 2021 | 339 mm1951 · driest 18 mm in 2016 | 56 |
| July | 41.7°C30 Jul 1980 | 5.0°C5 Jul 1972 | 117 mm7 Jul 2022 | 332 mm2020 · driest 7 mm in 2012 | 55 |
| August | 41.1°C25 Aug 2003 | 6.1°C18 Aug 2012 | 105 mm24 Aug 2007 | 250 mm1951 · driest 7 mm in 2015 | 53 |
| September | 39.4°C28 Sep 1953 | -1.1°C28 Sep 1967 | 120 mm13 Sep 2016 | 271 mm1970 · driest 0 mm in 2011 | 54 |
| October | 36.1°C10 Oct 1963 | -9.3°C18 Oct 2022 | 75 mm11 Oct 2021 | 209 mm1977 · driest 0 mm in 1975 | 55 |
| November | 27.8°C3 Nov 1978 | -18.9°C29 Nov 1976 | 62 mm29 Nov 1975 | 112 mm1998 · driest 0 mm in 1966 | 54 |
| December | 22.8°C15 Dec 2021 | -26.1°C9 Dec 2005 | 55 mm7 Dec 1980 | 89 mm2007 · driest 0 mm in 2002 | 54 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) | Snow days |
|---|---|---|---|---|---|
| January | 0 | 0 | 28 | <1 | 2 |
| February | <1 | 0 | 24 | <1 | 3 |
| March | 2 | 0 | 17 | 2 | 1 |
| April | 6 | 1 | 6 | 3 | 0 |
| May | 16 | 5 | <1 | 4 | 0 |
| June | 26 | 15 | 0 | 4 | 0 |
| July | 30 | 21 | 0 | 3 | 0 |
| August | 29 | 17 | 0 | 3 | 0 |
| September | 21 | 8 | <1 | 2 | 0 |
| October | 7 | 2 | 5 | 3 | 0 |
| November | <1 | 0 | 17 | 1 | 0 |
| December | 0 | 0 | 27 | <1 | <1 |
The best month has moved. On the 1961–1990 numbers the strongest month here was May (scoring 81); on 2011–2025 it is September (82). 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% | 12% | 2% | 6% | -0.6–5.5°C |
| February | 4% | 13% | 2% | 9% | 0.9–11.0°C |
| March | 17% | 20% | 6% | 18% | 8.4–16.6°C |
| April | 39% | 27% | 10% | 31% | 16.0–22.0°C |
| May | 60% | 29% | 13% | 35% | 22.2–27.0°C |
| June | 70% | 30% | 14% | 36% | 27.9–31.6°C |
| July | 77% | 22% | 9% | 22% | 29.1–33.8°C |
| August | 77% | 23% | 9% | 25% | 28.6–32.2°C |
| September | 76% | 21% | 8% | 19% | 24.8–28.8°C |
| October | 49% | 18% | 8% | 16% | 17.6–23.6°C |
| November | 14% | 14% | 4% | 8% | 8.3–15.3°C |
| December | <1% | 13% | 3% | 7% | 2.4–8.5°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