September
September · June · August
United States · 1991–2020
September leads for comfortable weather in Oglala: typically 25.7°C by day, 9°C at night, with 42 mm of rain. Based on measured 1991–2020 NOAA station history.
September · June · August
July · August · June
May · September · October
The weakest month is January, scoring 5 against September’s 81 — days reach only 3.5°C, 20° below the 24°C the score treats as ideal, and nights drop to -10°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 | 3.5°C | -10°C | 12 mm | 3 | 9 h 19 | 5 | Good coverage |
| February | 4.7°C | -9.1°C | 15 mm | 3.7 | 10 h 27 | 5 | Good coverage |
| March | 11.2°C | -4°C | 24 mm | 4.4 | 11 h 47 | 22 | Good coverage |
| April | 15.9°C | 1.2°C | 61 mm | 7.7 | 13 h 20 | 41 | Good coverage |
| May | 20.8°C | 6.4°C | 71 mm | 8.6 | 14 h 39 | 64 | Good coverage |
| June | 26.8°C | 11.9°C | 76 mm | 9.8 | 15 h 22 | 73 | Good coverage |
| July | 32.2°C | 16.2°C | 49 mm | 5.2 | 15 h 05 | 67 | Good coverage |
| August | 31.3°C | 14.6°C | 47 mm | 4.9 | 13 h 57 | 72 | Good coverage |
| September | 25.7°C | 9°C | 42 mm | 4.7 | 12 h 27 | 81 | Good coverage |
| October | 17.5°C | 1.9°C | 30 mm | 4 | 10 h 57 | 54 | Good coverage |
| November | 10.5°C | -4.1°C | 20 mm | 3.9 | 9 h 39 | 20 | Good coverage |
| December | 3.7°C | -9.6°C | 13 mm | 3.2 | 9 h | 5 | Good coverage |
| Month | Record high | Record low | Wettest day | Wettest / driest month | Years |
|---|---|---|---|---|---|
| January | 22.2°C28 Jan 2015 | -30.6°C8 Jan 2010 | 20 mm8 Jan 1999 | 25 mm1999 · driest 1 mm in 2014 | 18 |
| February | 23.3°C19 Feb 2016 | -31.7°C15 Feb 2007 | 36 mm26 Feb 2000 | 47 mm2000 · driest 3 mm in 2002 | 18 |
| March | 28.9°C29 Mar 2015 | -25.0°C2 Mar 2014 | 31 mm1 Mar 2004 | 51 mm2004 · driest 0 mm in 2012 | 18 |
| April | 32.2°C25 Apr 2012 | -15.0°C3 Apr 2002 | 68 mm19 Apr 2000 | 127 mm2000 · driest 12 mm in 2012 | 18 |
| May | 37.2°C20 May 2009 | -6.1°C8 May 2010 | 61 mm10 May 2015 | 160 mm2015 · driest 15 mm in 2004 | 18 |
| June | 42.8°C26 Jun 2007 | 1.7°C2 Jun 2000 | 64 mm16 Jun 2012 | 167 mm1999 · driest 12 mm in 2016 | 17 |
| July | 43.3°C26 Jul 2003 | 2.2°C3 Jul 2008 | 97 mm13 Jul 2006 | 113 mm2006 · driest 1 mm in 2005 | 18 |
| August | 41.7°C11 Aug 2007 | 1.1°C31 Aug 2009 | 47 mm13 Aug 2005 | 129 mm2014 · driest 13 mm in 2010 | 17 |
| September | 38.9°C5 Sep 2001 | -1.7°C19 Sep 2006 | 78 mm5 Sep 2004 | 118 mm2004 · driest 3 mm in 2012 | 18 |
| October | 33.9°C3 Oct 2011 | -12.8°C31 Oct 2002 | 57 mm5 Oct 2013 | 148 mm2013 · driest 4 mm in 2011 | 18 |
| November | 31.1°C3 Nov 2008 | -22.8°C23 Nov 2010 | 45 mm6 Nov 2008 | 80 mm2008 · driest 0 mm in 2007 | 18 |
| December | 22.2°C13 Dec 2014 | -30.0°C15 Dec 2008 | 20 mm26 Dec 2009 | 43 mm2009 · driest 0 mm in 2001 | 18 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) | Snow days |
|---|---|---|---|---|---|
| January | 0 | 0 | 29 | <1 | 5 |
| February | 0 | 0 | 26 | <1 | 6 |
| March | 1 | 0 | 23 | <1 | 4 |
| April | 4 | <1 | 12 | 2 | 3 |
| May | 9 | 2 | 3 | 2 | <1 |
| June | 19 | 9 | 0 | 2 | 0 |
| July | 27 | 21 | 0 | 1 | 0 |
| August | 26 | 19 | 0 | 2 | 0 |
| September | 17 | 8 | <1 | 1 | 0 |
| October | 5 | <1 | 10 | <1 | 1 |
| November | <1 | <1 | 23 | <1 | 4 |
| December | 0 | 0 | 29 | <1 | 5 |
| Month | Warm & dry days | Wet days | Washouts | Week with 3+ wet days | Daytime mean has ranged |
|---|---|---|---|---|---|
| January | <1% | 10% | <1% | 5% | 0.1–5.8°C |
| February | 1% | 12% | <1% | 5% | -0.3–9.4°C |
| March | 17% | 14% | 2% | 9% | 8.6–15.3°C |
| April | 28% | 25% | 6% | 30% | 13.1–18.7°C |
| May | 45% | 27% | 7% | 36% | 18.4–23.1°C |
| June | 63% | 31% | 7% | 32% | 24.7–30.1°C |
| July | 82% | 18% | 5% | 11% | 29.4–35.2°C |
| August | 85% | 16% | 5% | 12% | 29.7–33.4°C |
| September | 73% | 16% | 4% | 10% | 23.5–27.3°C |
| October | 39% | 13% | 3% | 8% | 12.5–20.2°C |
| November | 13% | 13% | 1% | 10% | 6.2–14.2°C |
| December | <1% | 10% | 1% | 6% | -0.2–7.3°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