September
September · August · June
United States · 1991–2020
September leads for comfortable weather in Sterling: typically 23.9°C by day, 10.7°C at night, with 86 mm of rain. Based on measured 1991–2020 NOAA station history.
September · August · June
July · August · June
May · September · October
The weakest month is January, scoring 5 against September’s 81 — days reach only 1.2°C, 23° 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 | 1.2°C | -7.5°C | 54 mm | 7.9 | 9 h 32 | 5 | Good coverage |
| February | 2.9°C | -6.4°C | 51 mm | 7.4 | 10 h 34 | 5 | Good coverage |
| March | 8.3°C | -2°C | 72 mm | 9.2 | 11 h 49 | 7 | Good coverage |
| April | 15.8°C | 3.3°C | 88 mm | 10.8 | 13 h 15 | 37 | Good coverage |
| May | 21.8°C | 9.3°C | 100 mm | 11 | 14 h 27 | 66 | Good coverage |
| June | 26.1°C | 14.4°C | 104 mm | 9.7 | 15 h 06 | 76 | Good coverage |
| July | 28°C | 16°C | 99 mm | 9.2 | 14 h 51 | 70 | Good coverage |
| August | 26.8°C | 14.6°C | 88 mm | 8.5 | 13 h 48 | 78 | Good coverage |
| September | 23.9°C | 10.7°C | 86 mm | 7.8 | 12 h 25 | 81 | Good coverage |
| October | 17.2°C | 5.1°C | 80 mm | 9.2 | 11 h 02 | 48 | Good coverage |
| November | 10°C | 0.1°C | 63 mm | 8.5 | 9 h 50 | 18 | Good coverage |
| December | 3.6°C | -4.1°C | 61 mm | 8.3 | 9 h 15 | 5 | Good coverage |
| Month | Record high | Record low | Wettest day | Wettest / driest month | Years |
|---|---|---|---|---|---|
| January | 19.4°C13 Jan 2005 | -30.0°C31 Jan 2026 | 39 mm12 Jan 2017 | 130 mm2005 · driest 14 mm in 2025 | 30 |
| February | 23.3°C20 Feb 2018 | -28.2°C24 Feb 2015 | 38 mm5 Feb 2008 | 125 mm2008 · driest 15 mm in 2014 | 30 |
| March | 27.8°C22 Mar 2012 | -22.7°C6 Mar 2015 | 38 mm7 Mar 2022 | 125 mm2008 · driest 27 mm in 2021 | 30 |
| April | 30.0°C25 Apr 2009 | -8.2°C4 Apr 2013 | 60 mm3 Apr 2018 | 167 mm2014 · driest 38 mm in 2006 | 30 |
| May | 33.9°C27 May 1998 | -2.1°C9 May 2020 | 58 mm1 May 2007 | 183 mm2011 · driest 31 mm in 2023 | 30 |
| June | 34.4°C28 Jun 2012 | 2.8°C2 Jun 2003 | 51 mm27 Jun 1998 | 187 mm2015 · driest 27 mm in 2007 | 30 |
| July | 35.0°C1 Jul 2026 | 7.8°C2 Jul 2007 | 79 mm31 Jul 2009 | 208 mm2003 · driest 24 mm in 2001 | 30 |
| August | 34.4°C1 Aug 2002 | 5.0°C30 Aug 2025 | 76 mm25 Aug 1998 | 171 mm1998 · driest 19 mm in 2025 | 29 |
| September | 33.9°C10 Sep 2013 | 0.0°C29 Sep 2000 | 51 mm9 Sep 2018 | 212 mm2012 · driest 16 mm in 2023 | 29 |
| October | 32.2°C8 Oct 2007 | -4.9°C30 Oct 2008 | 58 mm19 Oct 2011 | 174 mm2012 · driest 9 mm in 2024 | 29 |
| November | 25.6°C2 Nov 2016 | -13.2°C29 Nov 2013 | 70 mm18 Nov 2017 | 146 mm2017 · driest 11 mm in 2016 | 29 |
| December | 20.6°C5 Dec 2001 | -23.3°C25 Dec 2004 | 47 mm16 Dec 2000 | 104 mm2007 · driest 21 mm in 2010 | 29 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) |
|---|---|---|---|---|
| January | 0 | 0 | 27 | 2 |
| February | 0 | 0 | 25 | 2 |
| March | <1 | 0 | 22 | 3 |
| April | 3 | 0 | 9 | 3 |
| May | 10 | 2 | 1 | 3 |
| June | 20 | 6 | 0 | 4 |
| July | 26 | 9 | 0 | 3 |
| August | 24 | 5 | 0 | 3 |
| September | 13 | 3 | 0 | 3 |
| October | 4 | <1 | 6 | 2 |
| November | <1 | 0 | 16 | 2 |
| December | 0 | 0 | 25 | 2 |
| Month | Warm & dry days | Wet days | Washouts | Week with 3+ wet days | Daytime mean has ranged |
|---|---|---|---|---|---|
| January | 0% | 24% | 5% | 24% | -2.1–4.4°C |
| February | 1% | 24% | 5% | 24% | -0.9–7.2°C |
| March | 6% | 30% | 9% | 38% | 5.1–12.7°C |
| April | 20% | 36% | 10% | 50% | 13.3–18.2°C |
| May | 44% | 35% | 11% | 45% | 19.3–24.6°C |
| June | 65% | 32% | 12% | 39% | 24.8–27.4°C |
| July | 70% | 30% | 11% | 34% | 26.2–30.2°C |
| August | 71% | 28% | 9% | 30% | 25.5–28.4°C |
| September | 66% | 26% | 9% | 28% | 22.1–25.9°C |
| October | 28% | 29% | 8% | 30% | 15.7–19.8°C |
| November | 5% | 27% | 6% | 27% | 6.8–12.7°C |
| December | <1% | 27% | 6% | 31% | 1.2–7.7°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