September
September · August · June
82climate match
United States · 1991–2020
Best time to visit
Fairfax.
September leads for comfortable weather in Fairfax: typically 24°C by day, 11.1°C at night, with 86 mm of rain. Based on measured 1991–2020 NOAA station history.
Best comfortSeptember
Typical high24°C
Typical low11.1°C
Rain in September86 mm
July
July · August · June
69climate match
May
May · September · October
73climate match
The weakest month is January, scoring 5 against September’s 82 — days reach only -2.1°C, 26° 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
5-2.1° / -11.4°
Feb
50.5° / -9°
Mar
108.1° / -2.8°
Apr
3815.7° / 3.2°
May
6721.8° / 9.8°
Jun
6826.9° / 15.5°
Jul
6728.4° / 17.2°
Aug
7327.5° / 15.9°
Sep
8224° / 11.1°
Oct
4816.6° / 4.5°
Nov
128.1° / -2.3°
Dec
50.9° / -8.2°
| Month | Day | Night | Rain | Wet days | Daylight | Comfort | Coverage |
|---|---|---|---|---|---|---|---|
| January | -2.1°C | -11.4°C | 23 mm | 5 | 9 h 26 | 5 | Strong coverage |
| February | 0.5°C | -9°C | 31 mm | 4.9 | 10 h 31 | 5 | Strong coverage |
| March | 8.1°C | -2.8°C | 51 mm | 6.6 | 11 h 48 | 10 | Strong coverage |
| April | 15.7°C | 3.2°C | 91 mm | 9.3 | 13 h 17 | 38 | Strong coverage |
| May | 21.8°C | 9.8°C | 110 mm | 9.9 | 14 h 32 | 67 | Strong coverage |
| June | 26.9°C | 15.5°C | 141 mm | 10.2 | 15 h 13 | 68 | Strong coverage |
| July | 28.4°C | 17.2°C | 113 mm | 7.5 | 14 h 56 | 67 | Strong coverage |
| August | 27.5°C | 15.9°C | 103 mm | 7.9 | 13 h 52 | 73 | Strong coverage |
| September | 24°C | 11.1°C | 86 mm | 6.8 | 12 h 26 | 82 | Strong coverage |
| October | 16.6°C | 4.5°C | 73 mm | 6.6 | 11 h 00 | 48 | Strong coverage |
| November | 8.1°C | -2.3°C | 51 mm | 5.7 | 9 h 45 | 12 | Strong coverage |
| December | 0.9°C | -8.2°C | 37 mm | 5.2 | 9 h 08 | 5 | Strong coverage |
What has changed
Fairfax runs +0.9°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
+1.6
Feb
+0.6
Mar
+2.0
Apr
+0.3
May
+0.4
Jun
+0.5
Jul
-0.4
Aug
+0.2
Sep
+1.8
Oct
+0.2
Nov
+0.8
Dec
+2.9
| Month | Record high | Record low | Wettest day | Wettest / driest month | Years |
|---|---|---|---|---|---|
| January | 18.3°C31 Jan 1989 | -34.3°C31 Jan 2019 | 51 mm12 Jan 1960 | 107 mm1960 · driest 1 mm in 1981 | 73 |
| February | 24.4°C26 Feb 2024 | -32.2°C2 Feb 1996 | 36 mm2 Feb 1983 | 90 mm1962 · driest 0 mm in 2010 | 73 |
| March | 31.7°C21 Mar 2026 | -28.9°C1 Mar 1962 | 62 mm30 Mar 1998 | 155 mm1977 · driest 4 mm in 1981 | 73 |
| April | 35.0°C22 Apr 1980 | -17.2°C6 Apr 1982 | 83 mm13 Apr 2014 | 217 mm2013 · driest 11 mm in 2018 | 73 |
| May | 36.1°C27 May 2018 | -3.9°C3 May 2005 | 86 mm9 May 1996 | 256 mm1996 · driest 9 mm in 1981 | 73 |
| June | 37.8°C25 Jun 1954 | 3.9°C1 Jun 1993 | 121 mm16 Jun 1990 | 338 mm2014 · driest 4 mm in 1963 | 74 |
| July | 40.0°C31 Jul 1988 | 7.8°C4 Jul 1967 | 106 mm5 Jul 1993 | 433 mm1993 · driest 11 mm in 1991 | 74 |
| August | 38.9°C15 Aug 1988 | 4.4°C28 Aug 1986 | 136 mm27 Aug 2009 | 365 mm2009 · driest 3 mm in 2013 | 73 |
| September | 37.2°C9 Sep 2013 | -2.8°C29 Sep 1984 | 86 mm3 Sep 1958 | 261 mm1965 · driest 0 mm in 2024 | 73 |
| October | 34.4°C3 Oct 1997 | -9.4°C27 Oct 1997 | 64 mm31 Oct 1960 | 236 mm1998 · driest 1 mm in 1964 | 73 |
| November | 25.6°C8 Nov 1999 | -23.9°C26 Nov 1977 | 69 mm2 Nov 1961 | 164 mm1992 · driest 3 mm in 1955 | 73 |
| December | 22.8°C15 Dec 2021 | -30.0°C23 Dec 1989 | 46 mm13 Dec 2015 | 104 mm2015 · driest 6 mm in 1976 | 73 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) | Snow days |
|---|---|---|---|---|---|
| January | 0 | 0 | 30 | <1 | 6 |
| February | 0 | 0 | 26 | <1 | 4 |
| March | <1 | 0 | 23 | 2 | 3 |
| April | 3 | <1 | 8 | 3 | <1 |
| May | 10 | 2 | <1 | 4 | 0 |
| June | 22 | 8 | 0 | 4 | 0 |
| July | 27 | 11 | 0 | 4 | 0 |
| August | 25 | 7 | 0 | 3 | 0 |
| September | 14 | 4 | <1 | 3 | 0 |
| October | 3 | <1 | 7 | 2 | <1 |
| November | <1 | 0 | 21 | 2 | 2 |
| December | 0 | 0 | 29 | 1 | 5 |
| Month | Warm & dry days | Wet days | Washouts | Week with 3+ wet days | Daytime mean has ranged |
|---|---|---|---|---|---|
| January | 0% | 15% | 2% | 10% | -6.8–0.8°C |
| February | <1% | 15% | 2% | 11% | -4.0–5.1°C |
| March | 6% | 22% | 6% | 21% | 3.7–11.2°C |
| April | 21% | 29% | 10% | 33% | 12.7–18.5°C |
| May | 48% | 30% | 12% | 37% | 19.4–24.5°C |
| June | 68% | 29% | 13% | 33% | 24.9–28.9°C |
| July | 75% | 25% | 11% | 26% | 27.0–30.8°C |
| August | 76% | 24% | 10% | 25% | 25.7–29.6°C |
| September | 64% | 23% | 9% | 24% | 21.8–26.2°C |
| October | 29% | 20% | 7% | 21% | 14.1–19.5°C |
| November | 4% | 19% | 5% | 14% | 4.2–11.2°C |
| December | <1% | 18% | 4% | 12% | -3.5–4.4°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 4855958
- NOAA station
- USW00014990 · CEDAR RAPIDS MUNI AP
- Station distance
- 6.2 km from the place centre
- Climate period
- 1991–2020
- Minimum month coverage
- 29 usable years
- Daylight
- Calculated from latitude 41.92°, 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.