September
September · June · August
82climate match
United States · 1991–2020
Best time to visit
Riverton.
September leads for comfortable weather in Riverton: typically 24.2°C by day, 5.8°C at night, with 20 mm of rain. Based on measured 1991–2020 NOAA station history.
Best comfortSeptember
Typical high24.2°C
Typical low5.8°C
Rain in September20 mm
July
July · August · June
68climate match
May
May · September · June
83climate match
The weakest month is January, scoring 5 against September’s 82 — days reach only -1.3°C, 25° below the 24°C the score treats as ideal, and nights drop to -15.7°C.
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
5-1.3° / -15.7°
Feb
52.5° / -12.7°
Mar
1810.4° / -5.6°
Apr
4015.1° / -1°
May
6420.3° / 4.5°
Jun
7926.8° / 9°
Jul
7031.8° / 12.6°
Aug
7130.5° / 11.1°
Sep
8224.2° / 5.8°
Oct
4315.8° / -1°
Nov
56.6° / -8.4°
Dec
5-0.7° / -14.8°
| Month | Day | Night | Rain | Wet days | Daylight | Comfort | Coverage |
|---|---|---|---|---|---|---|---|
| January | -1.3°C | -15.7°C | 9 mm | 2.2 | 9 h 20 | 5 | Strong coverage |
| February | 2.5°C | -12.7°C | 11 mm | 2.7 | 10 h 27 | 5 | Strong coverage |
| March | 10.4°C | -5.6°C | 18 mm | 3.1 | 11 h 47 | 18 | Strong coverage |
| April | 15.1°C | -1°C | 33 mm | 5.1 | 13 h 20 | 40 | Strong coverage |
| May | 20.3°C | 4.5°C | 50 mm | 6.3 | 14 h 38 | 64 | Strong coverage |
| June | 26.8°C | 9°C | 28 mm | 4.3 | 15 h 20 | 79 | Strong coverage |
| July | 31.8°C | 12.6°C | 18 mm | 2.9 | 15 h 04 | 70 | Strong coverage |
| August | 30.5°C | 11.1°C | 12 mm | 2.9 | 13 h 56 | 71 | Strong coverage |
| September | 24.2°C | 5.8°C | 20 mm | 3.6 | 12 h 26 | 82 | Strong coverage |
| October | 15.8°C | -1°C | 24 mm | 3.8 | 10 h 57 | 43 | Strong coverage |
| November | 6.6°C | -8.4°C | 11 mm | 2.4 | 9 h 39 | 5 | Strong coverage |
| December | -0.7°C | -14.8°C | 8 mm | 2.6 | 9 h 01 | 5 | Strong coverage |
What has changed
Riverton runs +0.1°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
-0.9
Feb
-2.0
Mar
+0.8
Apr
-0.7
May
-1.0
Jun
+1.0
Jul
+0.2
Aug
-0.1
Sep
+1.3
Oct
-0.6
Nov
+1.3
Dec
+1.3
| Month | Record high | Record low | Wettest day | Wettest / driest month | Years |
|---|---|---|---|---|---|
| January | 17.2°C10 Jan 1953 | -43.3°C12 Jan 1963 | 22 mm16 Jan 1995 | 40 mm2023 · driest 0 mm in 1908 | 110 |
| February | 21.7°C11 Feb 1951 | -42.8°C8 Feb 1936 | 15 mm24 Feb 1935 | 34 mm2004 · driest 0 mm in 2009 | 111 |
| March | 28.9°C26 Mar 2026 | -31.1°C6 Mar 1920 | 38 mm31 Mar 2017 | 75 mm1998 · driest 0 mm in 1960 | 112 |
| April | 30.6°C29 Apr 1987 | -27.8°C2 Apr 1936 | 39 mm26 Apr 1971 | 119 mm2017 · driest 0 mm in 1987 | 112 |
| May | 35.6°C31 May 1984 | -9.4°C1 May 1909 | 63 mm30 May 1924 | 134 mm2011 · driest 2 mm in 1936 | 112 |
| June | 38.9°C28 Jun 1970 | -3.3°C3 Jun 1951 | 56 mm3 Jun 1993 | 151 mm1993 · driest 0 mm in 1942 | 110 |
| July | 40.0°C22 Jul 1982 | -1.1°C7 Jul 1986 | 48 mm24 Jul 1923 | 84 mm1923 · driest 0 mm in 1957 | 112 |
| August | 39.4°C1 Aug 1988 | -1.7°C31 Aug 1908 | 78 mm1 Aug 1912 | 129 mm1912 · driest 0 mm in 1969 | 111 |
| September | 36.7°C8 Sep 1990 | -12.8°C25 Sep 1926 | 54 mm27 Sep 1923 | 145 mm1923 · driest 0 mm in 1928 | 111 |
| October | 32.2°C1 Oct 1980 | -25.0°C30 Oct 2019 | 51 mm6 Oct 1912 | 129 mm1912 · driest 0 mm in 1933 | 112 |
| November | 22.8°C2 Nov 2014 | -33.3°C23 Nov 1985 | 33 mm24 Nov 2023 | 54 mm1996 · driest 0 mm in 1939 | 111 |
| December | 18.3°C2 Dec 1995 | -43.3°C31 Dec 1978 | 18 mm2 Dec 1982 | 24 mm1955 · driest 0 mm in 1950 | 108 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) | Snow days |
|---|---|---|---|---|---|
| January | 0 | 0 | 27 | <1 | 4 |
| February | 0 | 0 | 25 | <1 | 5 |
| March | 0 | 0 | 25 | <1 | 4 |
| April | 2 | <1 | 17 | 1 | 3 |
| May | 9 | 2 | 4 | 2 | 1 |
| June | 20 | 10 | 0 | <1 | 0 |
| July | 29 | 24 | 0 | <1 | 0 |
| August | 28 | 20 | <1 | <1 | 0 |
| September | 16 | 5 | 3 | <1 | <1 |
| October | 3 | 0 | 18 | <1 | 2 |
| November | 0 | 0 | 26 | <1 | 4 |
| December | 0 | 0 | 27 | 0 | 5 |
The best month has moved. On the 1961–1990 numbers the strongest month here was June (scoring 78); 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 | 0% | 6% | <1% | 2% | -7.6–3.7°C |
| February | <1% | 7% | <1% | 2% | -2.5–7.2°C |
| March | 5% | 10% | <1% | 4% | 5.9–13.1°C |
| April | 24% | 16% | 3% | 13% | 12.2–18.3°C |
| May | 53% | 19% | 4% | 19% | 17.7–23.5°C |
| June | 80% | 14% | 3% | 11% | 23.4–29.4°C |
| July | 89% | 10% | 2% | 4% | 29.7–33.5°C |
| August | 91% | 9% | <1% | 4% | 28.4–32.1°C |
| September | 75% | 11% | 2% | 7% | 21.5–26.6°C |
| October | 32% | 11% | 2% | 6% | 13.2–19.5°C |
| November | 1% | 7% | <1% | 2% | 1.9–10.2°C |
| December | 0% | 6% | <1% | 2% | -5.2–4.3°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 5836665
- NOAA station
- USC00487760 · RIVERTON
- Station distance
- 0.8 km from the place centre
- Climate period
- 1991–2020
- Minimum month coverage
- 28 usable years
- Daylight
- Calculated from latitude 43.02°, 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.