United States · 1991–2020

Best time to visit
Harrison.

September leads for comfortable weather in Harrison: typically 27.6°C by day, 13.7°C at night, with 69 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high27.6°C

Typical low13.7°C

Rain in September69 mm

Comfort

September

September · May · October

79climate match

Beach

August

August · July · June

76climate match

Outdoors

October

October · April · September

78climate match

The weakest month is January, scoring 5 against September’s 79 — days reach only 5.9°C, 18° 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

55.9° / -3.9°

Feb

88° / -2.3°

Mar

2814° / 2.5°

Apr

5520.3° / 7.8°

May

7425.1° / 13.3°

Jun

6130.1° / 18.1°

Jul

5431.4° / 20°

Aug

6230.8° / 18.5°

Sep

7927.6° / 13.7°

Oct

6621.2° / 7.3°

Nov

3214° / 2°

Dec

57.6° / -2.1°

Monthly climate evidence for Harrison — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	5.9°C	-3.9°C	66 mm	6.7	9 h 49	5	Good coverage
February	8°C	-2.3°C	71 mm	6.4	10 h 44	8	Good coverage
March	14°C	2.5°C	110 mm	9.1	11 h 50	28	Good coverage
April	20.3°C	7.8°C	133 mm	9.5	13 h 07	55	Good coverage
May	25.1°C	13.3°C	121 mm	10.5	14 h 11	74	Good coverage
June	30.1°C	18.1°C	102 mm	7.9	14 h 46	61	Good coverage
July	31.4°C	20°C	101 mm	7.2	14 h 32	54	Good coverage
August	30.8°C	18.5°C	82 mm	6.7	13 h 37	62	Good coverage
September	27.6°C	13.7°C	69 mm	5.2	12 h 23	79	Good coverage
October	21.2°C	7.3°C	93 mm	6.4	11 h 09	66	Good coverage
November	14°C	2°C	90 mm	7.4	10 h 05	32	Good coverage
December	7.6°C	-2.1°C	85 mm	7.2	9 h 33	5	Good coverage

Records at CARBONDALE STHRN ILLINOIS AP, 1998–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	21.7°C29 Jan 2002	-21.1°C24 Jan 2003	52 mm12 Jan 2013	153 mm2020 · driest 8 mm in 2011	28
February	26.1°C27 Feb 2024	-21.6°C19 Feb 2015	52 mm15 Feb 2025	148 mm2019 · driest 13 mm in 2026	28
March	30.0°C22 Mar 2026	-19.3°C6 Mar 2015	149 mm18 Mar 2008	280 mm2008 · driest 18 mm in 2024	28
April	31.1°C30 Apr 2007	-4.9°C8 Apr 2007	121 mm29 Apr 2017	343 mm2011 · driest 48 mm in 2000	28
May	35.0°C26 May 2012	0.6°C9 May 2020	55 mm1 May 2011	218 mm2004 · driest 34 mm in 2012	28
June	41.7°C29 Jun 2012	6.7°C1 Jun 2003	106 mm16 Jun 2000	283 mm2000 · driest 17 mm in 2022	28
July	41.7°C6 Jul 2012	10.6°C28 Jul 2013	108 mm6 Jul 2016	254 mm2016 · driest 0 mm in 2002	28
August	40.0°C4 Aug 2010	7.2°C26 Aug 2025	84 mm4 Aug 2012	203 mm2001 · driest 1 mm in 2025	28
September	37.2°C21 Sep 2022	0.6°C30 Sep 2022	83 mm25 Sep 2011	165 mm2021 · driest 10 mm in 2019	28
October	35.0°C2 Oct 2019	-5.5°C20 Oct 2022	94 mm26 Oct 2019	249 mm2009 · driest 19 mm in 2024	28
November	27.8°C1 Nov 2016	-12.7°C12 Nov 2019	98 mm15 Nov 2005	183 mm2011 · driest 7 mm in 1999	28
December	23.9°C2 Dec 2021	-23.9°C25 Dec 2004	69 mm9 Dec 1999	179 mm2007 · driest 15 mm in 2025	28

Typical days per month at CARBONDALE STHRN ILLINOIS AP, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	0	0	24	2
February	0	0	19	3
March	2	0	11	4
April	7	<1	3	4
May	18	5	0	4
June	28	17	0	3
July	30	23	0	3
August	30	20	0	3
September	23	10	0	2
October	10	2	3	3
November	<1	0	13	3
December	0	0	21	3

How often, not how much — every day in CARBONDALE STHRN ILLINOIS AP’s record sorted by what it was actually like, rather than averaged
Month	Warm & dry days	Wet days	Washouts	Week with 3+ wet days	Daytime mean has ranged
January	<1%	20%	7%	18%	3.0–8.8°C
February	4%	22%	8%	21%	4.0–12.1°C
March	17%	28%	12%	34%	11.0–18.3°C
April	39%	32%	15%	43%	18.7–22.8°C
May	59%	33%	13%	41%	23.4–26.9°C
June	75%	25%	10%	26%	28.8–31.6°C
July	76%	24%	10%	24%	29.3–33.2°C
August	80%	21%	8%	16%	29.1–32.2°C
September	81%	17%	8%	13%	25.6–29.6°C
October	52%	21%	9%	22%	18.9–23.6°C
November	15%	23%	9%	24%	10.9–16.7°C
December	2%	23%	10%	22%	5.7–10.7°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.

1999Each stripe is one year’s mean temperature against the 27-year average. Warmest: 2024. Coolest: 2014.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4240292
NOAA station: USW00093810 · CARBONDALE STHRN ILLINOIS AP
Station distance: 8.2 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 22 usable years
Daylight: Calculated from latitude 37.80°, 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.

These places read the same station, so their numbers are identical — distance from CARBONDALE STHRN ILLINOIS AP is what differs

Murphysboro→De Soto→Hurst→Ava→Vergennes→Bush→

Or put two places side by side: Harrison vs Murphysboro

Best time to visitHarrison.