United States · 1991–2020

Best time to visit
Union.

September leads for comfortable weather in Union: typically 27.4°C by day, 13.4°C at night, with 100 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high27.4°C

Typical low13.4°C

Rain in September100 mm

Comfort

September

September · May · October

73climate match

Beach

August

August · June · July

71climate match

Outdoors

October

October · April · May

81climate match

The weakest month is January, scoring 5 against September’s 73 — days reach only 6°C, 18° below the 24°C the score treats as ideal, and nights drop to -5°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

56° / -5°

Feb

149.5° / -2.9°

Mar

3214.9° / 1.4°

Apr

5921.1° / 7.1°

May

7225.4° / 12.4°

Jun

6229.7° / 17.1°

Jul

4932.2° / 19.6°

Aug

5632° / 18.8°

Sep

7327.4° / 13.4°

Oct

6921.4° / 7.4°

Nov

2913.7° / 1.8°

Dec

57.6° / -2.9°

Monthly climate evidence for Union — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	6°C	-5°C	74 mm	7.4	9 h 45	5	Good coverage
February	9.5°C	-2.9°C	60 mm	6.1	10 h 42	14	Good coverage
March	14.9°C	1.4°C	92 mm	8.7	11 h 50	32	Good coverage
April	21.1°C	7.1°C	117 mm	9.7	13 h 09	59	Good coverage
May	25.4°C	12.4°C	118 mm	10.4	14 h 14	72	Good coverage
June	29.7°C	17.1°C	108 mm	8.4	14 h 50	62	Good coverage
July	32.2°C	19.6°C	112 mm	7.8	14 h 36	49	Good coverage
August	32°C	18.8°C	89 mm	6.9	13 h 39	56	Good coverage
September	27.4°C	13.4°C	100 mm	6.6	12 h 23	73	Good coverage
October	21.4°C	7.4°C	73 mm	6.6	11 h 08	69	Good coverage
November	13.7°C	1.8°C	101 mm	7.8	10 h 02	29	Good coverage
December	7.6°C	-2.9°C	70 mm	7.1	9 h 30	5	Good coverage

Records at UNION, 1937–2009
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	25.6°C24 Jan 1943	-32.2°C17 Jan 1977	78 mm5 Jan 2005	199 mm2005 · driest 2 mm in 1986	72
February	29.4°C13 Feb 1962	-32.2°C2 Feb 1951	67 mm10 Feb 1959	152 mm2008 · driest 4 mm in 1963	72
March	31.7°C31 Mar 1940	-23.3°C24 Mar 1974	64 mm28 Mar 1977	223 mm1945 · driest 17 mm in 1941	72
April	34.4°C26 Apr 1989	-8.3°C1 Apr 1954	111 mm29 Apr 1996	316 mm1994 · driest 24 mm in 1977	72
May	36.1°C26 May 1953	-2.2°C2 May 1961	79 mm31 May 1942	268 mm1942 · driest 22 mm in 2005	72
June	42.8°C29 Jun 1952	1.7°C1 Jun 1972	192 mm15 Jun 1957	553 mm1957 · driest 9 mm in 1952	72
July	47.8°C14 Jul 1954	6.7°C6 Jul 1972	115 mm26 Jul 1948	326 mm2008 · driest 5 mm in 1974	73
August	42.8°C29 Aug 1984	5.0°C29 Aug 1986	98 mm21 Aug 1951	211 mm1950 · driest 10 mm in 1947	72
September	42.8°C4 Sep 1947	-1.7°C28 Sep 1942	121 mm23 Sep 1993	375 mm1993 · driest 1 mm in 1979	71
October	35.6°C5 Oct 1938	-10.6°C29 Oct 1952	83 mm31 Oct 1942	214 mm1949 · driest 9 mm in 1952	71
November	30.6°C1 Nov 1937	-18.3°C25 Nov 1950	128 mm1 Nov 1946	297 mm1985 · driest 3 mm in 1949	71
December	25.0°C8 Dec 1991	-30.6°C23 Dec 1989	91 mm27 Dec 1942	220 mm1987 · driest 1 mm in 1955	72

Typical days per month at UNION, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	<1	0	25	2	3
February	<1	0	20	2	2
March	3	<1	14	3	1
April	10	2	4	4	<1
May	18	5	<1	4	0
June	27	16	0	4	0
July	31	24	0	3	0
August	30	22	0	3	0
September	22	9	<1	3	0
October	9	2	3	3	0
November	1	0	13	3	<1
December	<1	0	22	2	2

How often, not how much — every day in UNION’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	3%	21%	5%	18%	2.3–9.5°C
February	7%	21%	6%	19%	4.7–12.5°C
March	20%	27%	9%	31%	10.4–17.8°C
April	43%	32%	12%	40%	18.3–23.4°C
May	64%	31%	12%	38%	23.3–27.9°C
June	72%	27%	12%	30%	27.8–31.8°C
July	76%	23%	9%	20%	30.6–34.5°C
August	78%	23%	9%	24%	29.6–34.8°C
September	76%	22%	10%	20%	25.2–30.4°C
October	55%	22%	9%	24%	19.7–24.4°C
November	19%	24%	9%	23%	10.5–16.7°C
December	4%	22%	7%	21%	4.5–10.8°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.

1938Each stripe is one year’s mean temperature against the 66-year average. Warmest: 1938. Coolest: 1978.2008

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4412454
NOAA station: USC00238515 · UNION
Station distance: 0.7 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 18 usable years
Daylight: Calculated from latitude 38.45°, 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 UNION is what differs

Saint Clair→Villa Ridge→Oak Grove Village→Parkway→Miramiguoa Park→Charmwood→

Or put two places side by side: Union vs Saint Clair

Best time to visitUnion.