September
September · June · August
90climate match
United States · 1991–2020
Best time to visit
Collister.
September leads for comfortable weather in Collister: typically 24.5°C by day, 10.3°C at night, with 14 mm of rain. Based on measured 1991–2020 NOAA station history.
Best comfortSeptember
Typical high24.5°C
Typical low10.3°C
Rain in September14 mm
August
August · July · September
78climate match
September
September · May · June
86climate match
The weakest month is January, scoring 5 against September’s 90 — days reach only 2.8°C, 21° below the 24°C the score treats as ideal.
Month by month
The whole year,
without the guesswork.
The bars show the comfort score. Day and night temperatures come from daily observed highs and lows; rain is the historical monthly estimate.
Jan
52.8° / -4.6°
Feb
55.9° / -2.7°
Mar
2310.8° / 0.3°
Apr
3914.3° / 2.3°
May
6419.8° / 6°
Jun
8624.7° / 9.3°
Jul
7631° / 14.5°
Aug
7930.2° / 14.5°
Sep
9024.5° / 10.3°
Oct
5416.3° / 4.5°
Nov
117.9° / -1°
Dec
52.7° / -4.7°
| Month | Day | Night | Rain | Wet days | Daylight | Comfort | Coverage |
|---|---|---|---|---|---|---|---|
| January | 2.8°C | -4.6°C | 59 mm | 9.2 | 9 h 16 | 5 | Strong coverage |
| February | 5.9°C | -2.7°C | 41 mm | 8 | 10 h 25 | 5 | Strong coverage |
| March | 10.8°C | 0.3°C | 53 mm | 8.6 | 11 h 47 | 23 | Strong coverage |
| April | 14.3°C | 2.3°C | 49 mm | 7.8 | 13 h 22 | 39 | Strong coverage |
| May | 19.8°C | 6°C | 53 mm | 7.2 | 14 h 41 | 64 | Strong coverage |
| June | 24.7°C | 9.3°C | 32 mm | 4.9 | 15 h 25 | 86 | Strong coverage |
| July | 31°C | 14.5°C | 7 mm | 1.7 | 15 h 08 | 76 | Strong coverage |
| August | 30.2°C | 14.5°C | 5 mm | 1 | 13 h 59 | 79 | Strong coverage |
| September | 24.5°C | 10.3°C | 14 mm | 2.8 | 12 h 27 | 90 | Strong coverage |
| October | 16.3°C | 4.5°C | 32 mm | 4.6 | 10 h 56 | 54 | Strong coverage |
| November | 7.9°C | -1°C | 49 mm | 8.6 | 9 h 36 | 11 | Strong coverage |
| December | 2.7°C | -4.7°C | 64 mm | 9.9 | 8 h 57 | 5 | Strong coverage |
What has changed
Collister runs +0.4°C
on the 1961–1990 baseline.
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.
Jan
+1.3
Feb
+0.8
Mar
+1.3
Apr
-0.3
May
+0.3
Jun
-0.9
Jul
+0.1
Aug
+0.1
Sep
+0.4
Oct
-0.5
Nov
+0.9
Dec
+1.1
| Month | Record high | Record low | Wettest day | Wettest / driest month | Years |
|---|---|---|---|---|---|
| January | 16.1°C31 Jan 2024 | -23.3°C6 Jan 2017 | 50 mm19 Jan 2012 | 123 mm2017 · driest 6 mm in 1985 | 50 |
| February | 19.4°C24 Feb 1986 | -26.7°C5 Feb 1989 | 33 mm12 Feb 1975 | 157 mm1986 · driest 6 mm in 1997 | 50 |
| March | 25.0°C26 Mar 2025 | -12.8°C5 Mar 1976 | 30 mm30 Mar 2017 | 134 mm1983 · driest 6 mm in 1994 | 49 |
| April | 31.1°C27 Apr 1987 | -7.8°C5 Apr 1997 | 37 mm26 Apr 2012 | 114 mm1978 · driest 8 mm in 1977 | 49 |
| May | 35.0°C30 May 1986 | -6.7°C2 May 1988 | 36 mm22 May 2010 | 181 mm1998 · driest 0 mm in 1992 | 52 |
| June | 40.0°C28 Jun 2015 | -2.2°C7 Jun 1995 | 58 mm11 Jun 1976 | 96 mm2009 · driest 0 mm in 2025 | 52 |
| July | 40.6°C19 Jul 1989 | 2.2°C8 Jul 1981 | 35 mm28 Jul 1984 | 42 mm1983 · driest 0 mm in 2023 | 51 |
| August | 41.1°C6 Aug 1990 | 1.1°C24 Aug 1992 | 42 mm13 Aug 1979 | 70 mm1979 · driest 0 mm in 2012 | 51 |
| September | 37.8°C1 Sep 1987 | -2.8°C24 Sep 1984 | 50 mm10 Sep 1980 | 111 mm1986 · driest 0 mm in 1987 | 51 |
| October | 33.3°C1 Oct 1992 | -11.1°C31 Oct 2002 | 42 mm24 Oct 2010 | 101 mm2000 · driest 0 mm in 1988 | 52 |
| November | 22.2°C7 Nov 1999 | -20.0°C24 Nov 1993 | 28 mm1 Nov 2014 | 129 mm1988 · driest 5 mm in 1976 | 51 |
| December | 16.7°C6 Dec 1987 | -30.6°C22 Dec 1990 | 34 mm25 Dec 1996 | 173 mm1996 · driest 3 mm in 1989 | 51 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) | Snow days |
|---|---|---|---|---|---|
| January | 0 | 0 | 27 | 2 | 8 |
| February | 0 | 0 | 21 | <1 | 6 |
| March | 0 | 0 | 15 | 1 | 5 |
| April | <1 | 0 | 9 | 1 | 2 |
| May | 6 | 1 | 3 | 2 | <1 |
| June | 15 | 5 | <1 | <1 | <1 |
| July | 28 | 20 | 0 | <1 | 0 |
| August | 28 | 18 | 0 | <1 | 0 |
| September | 16 | 4 | <1 | <1 | 0 |
| October | 2 | <1 | 5 | <1 | <1 |
| November | 0 | 0 | 17 | 1 | 4 |
| December | 0 | 0 | 26 | 2 | 9 |
| Month | Warm & dry days | Wet days | Washouts | Week with 3+ wet days | Daytime mean has ranged |
|---|---|---|---|---|---|
| January | 0% | 30% | 5% | 37% | -1.0–5.0°C |
| February | 0% | 31% | 4% | 40% | 3.0–8.1°C |
| March | 2% | 29% | 5% | 36% | 8.1–13.5°C |
| April | 17% | 25% | 5% | 27% | 12.6–17.8°C |
| May | 46% | 22% | 5% | 25% | 17.6–22.0°C |
| June | 76% | 14% | 3% | 10% | 22.6–28.4°C |
| July | 94% | 6% | <1% | 3% | 29.1–33.7°C |
| August | 94% | 5% | <1% | 3% | 28.6–31.8°C |
| September | 75% | 11% | 2% | 9% | 22.4–26.8°C |
| October | 28% | 15% | 3% | 15% | 14.6–19.2°C |
| November | <1% | 31% | 5% | 42% | 5.4–10.4°C |
| December | 0% | 32% | 6% | 40% | -0.2–5.3°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
Nearby, measured,
and named.
- Place identity
- GeoNames 5589332
- NOAA station
- USC00101017 · BOISE 7 N
- Station distance
- 9.6 km from the place centre
- Climate period
- 1991–2020
- Minimum month coverage
- 29 usable years
- Daylight
- Calculated from latitude 43.66°, mid-month, sunrise to sunset including refraction. Not a station measurement.
- Important limit
- Historical climate is not a forecast. Nearby stations can miss mountains, coasts, and local microclimates.