United States · 1991–2020

Best time to visit
Troy.

September leads for comfortable weather in Troy: typically 28.3°C by day, 14°C at night, with 86 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high28.3°C

Typical low14°C

Rain in September86 mm

Comfort

September

September · May · October

75climate match

Beach

July

July · August · June

72climate match

Outdoors

October

October · April · March

77climate match

The weakest month is January, scoring 5 against September’s 75 — 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° / -4.2°

Feb

149° / -2.2°

Mar

3614.9° / 2.5°

Apr

6021.2° / 7.9°

May

7225.9° / 13.6°

Jun

5730.5° / 18.2°

Jul

5132.1° / 20°

Aug

5731.5° / 18.6°

Sep

7528.3° / 14°

Oct

7222.4° / 8.1°

Nov

3514.3° / 2.7°

Dec

87.8° / -2°

Monthly climate evidence for Troy — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	5.9°C	-4.2°C	64 mm	6	9 h 44	5	Strong coverage
February	9°C	-2.2°C	55 mm	5.9	10 h 41	14	Strong coverage
March	14.9°C	2.5°C	86 mm	8.2	11 h 50	36	Strong coverage
April	21.2°C	7.9°C	124 mm	9.1	13 h 09	60	Strong coverage
May	25.9°C	13.6°C	128 mm	10.1	14 h 16	72	Strong coverage
June	30.5°C	18.2°C	117 mm	7.8	14 h 52	57	Strong coverage
July	32.1°C	20°C	102 mm	6.6	14 h 37	51	Strong coverage
August	31.5°C	18.6°C	99 mm	6.3	13 h 40	57	Strong coverage
September	28.3°C	14°C	86 mm	5.5	12 h 23	75	Strong coverage
October	22.4°C	8.1°C	79 mm	7.1	11 h 07	72	Strong coverage
November	14.3°C	2.7°C	88 mm	6.7	10 h 01	35	Strong coverage
December	7.8°C	-2°C	66 mm	6.6	9 h 28	8	Strong coverage

What has changed

Troy runs +1.4°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

+1.7

Feb

+1.9

Mar

+2.1

Apr

+0.9

May

+1.1

Jun

+1.2

Jul

+0.4

Aug

+0.4

Sep

+1.5

Oct

+1.4

Nov

+1.0

Dec

+2.8

September daytime highs, 2011–2025. Last recorded: 30.0°C.

Records at BELLEVILLE SIU RSCH, 1948–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	23.9°C24 Jan 1950	-32.8°C17 Jan 1977	91 mm3 Jan 1950	231 mm1950 · driest 0 mm in 2025	78
February	28.3°C28 Feb 2024	-29.4°C10 Feb 1982	114 mm2 Feb 1986	203 mm1986 · driest 0 mm in 2024	78
March	33.2°C22 Mar 2026	-22.2°C5 Mar 1978	68 mm19 Mar 2008	247 mm2008 · driest 9 mm in 1967	78
April	32.8°C30 Apr 2007	-7.8°C8 Apr 2007	116 mm29 Apr 1996	291 mm1994 · driest 23 mm in 1977	78
May	36.1°C26 May 1953	-2.2°C4 May 1976	116 mm17 May 1995	433 mm1995 · driest 21 mm in 2005	78
June	41.1°C28 Jun 2012	3.3°C1 Jun 1972	207 mm15 Jun 1957	436 mm1957 · driest 4 mm in 2023	79
July	43.3°C14 Jul 1954	6.1°C6 Jul 1972	100 mm28 Jul 1979	242 mm2010 · driest 9 mm in 1975	79
August	40.6°C16 Aug 2007	3.9°C29 Aug 1986	102 mm12 Aug 2020	265 mm2020 · driest 1 mm in 2023	78
September	39.4°C5 Sep 1954	-3.3°C23 Sep 1995	106 mm8 Sep 2018	241 mm2005 · driest 2 mm in 2004	77
October	35.6°C1 Oct 2019	-7.2°C17 Oct 2024	88 mm30 Oct 2009	306 mm2009 · driest 1 mm in 2023	78
November	28.9°C1 Nov 1950	-16.7°C8 Nov 1991	114 mm6 Nov 2024	277 mm1972 · driest 4 mm in 1980	78
December	25.3°C28 Dec 2025	-28.3°C22 Dec 1989	101 mm3 Dec 1982	237 mm1982 · driest 0 mm in 1979	77

Typical days per month at BELLEVILLE SIU RSCH, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	23	2	2
February	<1	0	19	2	2
March	3	<1	12	3	<1
April	9	<1	3	4	0
May	19	7	0	4	0
June	28	19	0	4	0
July	30	24	0	3	0
August	30	23	0	3	0
September	24	12	<1	2	0
October	12	3	3	3	0
November	1	0	11	3	<1
December	0	0	21	2	2

How often, not how much — every day in BELLEVILLE SIU RSCH’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	2%	18%	5%	16%	1.2–8.1°C
February	5%	20%	7%	17%	3.8–11.2°C
March	17%	26%	10%	29%	9.7–17.4°C
April	39%	29%	12%	35%	17.3–23.3°C
May	63%	29%	12%	34%	22.8–27.7°C
June	75%	25%	11%	26%	27.9–32.3°C
July	79%	22%	10%	18%	30.0–33.8°C
August	81%	20%	9%	17%	29.3–32.9°C
September	79%	18%	8%	14%	25.2–30.1°C
October	52%	21%	8%	22%	19.4–24.0°C
November	16%	22%	9%	19%	10.5–16.9°C
December	2%	20%	7%	18%	3.4–10.4°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.

1949Each stripe is one year’s mean temperature against the 74-year average. Warmest: 2012. Coolest: 1979.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4251513
NOAA station: USW00013802 · BELLEVILLE SIU RSCH
Station distance: 23.5 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 29 usable years
Daylight: Calculated from latitude 38.73°, 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 BELLEVILLE SIU RSCH is what differs

Belleville→O'Fallon→Swansea→Shiloh→Highland→Mascoutah→

Or put two places side by side: Troy vs Belleville

Best time to visitTroy.