September
September · August · June
80climate match
United States · 1991–2020
Best time to visit
Rock Rapids.
September leads for comfortable weather in Rock Rapids: typically 24°C by day, 9.7°C at night, with 85 mm of rain. Based on measured 1991–2020 NOAA station history.
Best comfortSeptember
Typical high24°C
Typical low9.7°C
Rain in September85 mm
July
July · August · June
73climate match
September
September · May · October
74climate match
The weakest month is January, scoring 5 against September’s 80 — days reach only -3.8°C, 28° 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
5-3.8° / -14.5°
Feb
5-0.9° / -12.2°
Mar
56.2° / -5.6°
Apr
3314.4° / 0.8°
May
6221.3° / 8.1°
Jun
7027.1° / 14.5°
Jul
6929.3° / 16.4°
Aug
7627.9° / 14.8°
Sep
8024° / 9.7°
Oct
4516.2° / 2.2°
Nov
66.8° / -5.1°
Dec
5-0.9° / -11.2°
| Month | Day | Night | Rain | Wet days | Daylight | Comfort | Coverage |
|---|---|---|---|---|---|---|---|
| January | -3.8°C | -14.5°C | 15 mm | 3.4 | 9 h 17 | 5 | Strong coverage |
| February | -0.9°C | -12.2°C | 18 mm | 4 | 10 h 26 | 5 | Strong coverage |
| March | 6.2°C | -5.6°C | 38 mm | 5 | 11 h 47 | 5 | Strong coverage |
| April | 14.4°C | 0.8°C | 77 mm | 7.8 | 13 h 21 | 33 | Strong coverage |
| May | 21.3°C | 8.1°C | 105 mm | 10.9 | 14 h 40 | 62 | Strong coverage |
| June | 27.1°C | 14.5°C | 128 mm | 9.3 | 15 h 23 | 70 | Strong coverage |
| July | 29.3°C | 16.4°C | 88 mm | 6.6 | 15 h 06 | 69 | Strong coverage |
| August | 27.9°C | 14.8°C | 80 mm | 7.9 | 13 h 58 | 76 | Strong coverage |
| September | 24°C | 9.7°C | 85 mm | 6.4 | 12 h 27 | 80 | Strong coverage |
| October | 16.2°C | 2.2°C | 58 mm | 5.7 | 10 h 56 | 45 | Strong coverage |
| November | 6.8°C | -5.1°C | 36 mm | 4.1 | 9 h 37 | 6 | Strong coverage |
| December | -0.9°C | -11.2°C | 21 mm | 4.3 | 8 h 58 | 5 | Strong coverage |
What has changed
Rock Rapids runs +0.0°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
+0.7
Feb
-1.0
Mar
+1.0
Apr
-1.5
May
-1.0
Jun
+0.4
Jul
-0.9
Aug
-1.1
Sep
+1.8
Oct
-0.3
Nov
+0.7
Dec
+1.7
| Month | Record high | Record low | Wettest day | Wettest / driest month | Years |
|---|---|---|---|---|---|
| January | 20.0°C27 Jan 2002 | -40.0°C12 Jan 1912 | 28 mm11 Jan 1975 | 57 mm1975 · driest 0 mm in 2002 | 128 |
| February | 21.1°C26 Feb 1896 | -40.0°C9 Feb 1899 | 44 mm28 Feb 1951 | 86 mm1962 · driest 0 mm in 1931 | 125 |
| March | 32.2°C24 Mar 1967 | -30.6°C11 Mar 1948 | 52 mm31 Mar 2006 | 129 mm1987 · driest 0 mm in 1910 | 127 |
| April | 35.0°C27 Apr 1987 | -16.1°C3 Apr 1936 | 91 mm23 Apr 2001 | 182 mm2001 · driest 4 mm in 1926 | 128 |
| May | 41.1°C30 May 1934 | -6.7°C3 May 1967 | 89 mm22 May 1936 | 240 mm1959 · driest 8 mm in 1894 | 127 |
| June | 41.7°C22 Jun 1988 | 0.0°C9 Jun 1915 | 163 mm22 Jun 2024 | 440 mm2024 · driest 12 mm in 2012 | 127 |
| July | 43.9°C17 Jul 1936 | 0.0°C9 Jul 1895 | 131 mm22 Jul 2010 | 228 mm2010 · driest 0 mm in 1947 | 127 |
| August | 42.8°C24 Aug 1936 | 1.1°C14 Aug 1895 | 105 mm16 Aug 1977 | 239 mm1979 · driest 8 mm in 1970 | 126 |
| September | 40.0°C7 Sep 1976 | -7.8°C27 Sep 1893 | 163 mm1 Sep 1933 | 233 mm1938 · driest 6 mm in 2024 | 127 |
| October | 34.4°C5 Oct 1963 | -23.3°C29 Oct 1925 | 69 mm16 Oct 1968 | 163 mm1968 · driest 0 mm in 1952 | 127 |
| November | 26.7°C9 Nov 1999 | -28.9°C14 Nov 1959 | 65 mm20 Nov 1975 | 140 mm2015 · driest 0 mm in 1912 | 125 |
| December | 21.1°C4 Dec 1998 | -34.4°C29 Dec 1917 | 40 mm30 Dec 1931 | 74 mm1982 · driest 0 mm in 1905 | 126 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) | Snow days |
|---|---|---|---|---|---|
| January | 0 | 0 | 30 | <1 | 4 |
| February | 0 | 0 | 28 | <1 | 4 |
| March | <1 | 0 | 26 | 1 | 2 |
| April | 3 | <1 | 13 | 3 | 1 |
| May | 10 | 3 | 1 | 3 | 0 |
| June | 21 | 9 | 0 | 4 | 0 |
| July | 27 | 14 | 0 | 3 | 0 |
| August | 25 | 10 | 0 | 3 | 0 |
| September | 14 | 5 | 1 | 2 | 0 |
| October | 4 | <1 | 12 | 2 | <1 |
| November | <1 | 0 | 25 | 1 | 2 |
| December | 0 | 0 | 30 | <1 | 4 |
| Month | Warm & dry days | Wet days | Washouts | Week with 3+ wet days | Daytime mean has ranged |
|---|---|---|---|---|---|
| January | 0% | 11% | <1% | 6% | -8.2–1.1°C |
| February | <1% | 12% | 1% | 7% | -5.5–3.9°C |
| March | 5% | 17% | 4% | 14% | 1.5–10.4°C |
| April | 23% | 24% | 8% | 26% | 11.3–18.4°C |
| May | 49% | 29% | 10% | 34% | 19.3–24.9°C |
| June | 68% | 28% | 12% | 33% | 24.7–29.6°C |
| July | 78% | 22% | 9% | 19% | 27.7–32.0°C |
| August | 77% | 22% | 8% | 19% | 26.8–30.7°C |
| September | 65% | 20% | 8% | 19% | 21.3–26.5°C |
| October | 32% | 15% | 5% | 11% | 12.9–19.5°C |
| November | 4% | 13% | 3% | 8% | 2.7–10.4°C |
| December | 0% | 12% | 2% | 8% | -5.3–2.7°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
Nearby, measured,
and named.
- Place identity
- GeoNames 4873354
- NOAA station
- USC00137147 · ROCK RAPIDS
- Station distance
- 0.6 km from the place centre
- Climate period
- 1991–2020
- Minimum month coverage
- 28 usable years
- Daylight
- Calculated from latitude 43.43°, 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.