United States · 1991–2020

Best time to visit
Pomona.

September leads for comfortable weather in Pomona: typically 27.1°C by day, 14.5°C at night, with 107 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high27.1°C

Typical low14.5°C

Rain in September107 mm

Comfort

September

September · May · October

75climate match

Beach

July

July · August · June

73climate match

Outdoors

October

October · April · March

84climate match

The weakest month is January, scoring 5 against September’s 75 — days reach only 4.6°C, 19° below the 24°C the score treats as ideal, and nights drop to -6.6°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

54.6° / -6.6°

Feb

87.3° / -4.7°

Mar

3513.5° / 0.7°

Apr

5519° / 6.3°

May

7423.9° / 12.6°

Jun

5829.3° / 18.1°

Jul

5032.1° / 20.4°

Aug

5431.4° / 19.4°

Sep

7527.1° / 14.5°

Oct

6620.4° / 7.7°

Nov

3412.8° / 1.1°

Dec

76.6° / -3.9°

Monthly climate evidence for Pomona — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	4.6°C	-6.6°C	22 mm	3.4	9 h 45	5	Strong coverage
February	7.3°C	-4.7°C	40 mm	4.1	10 h 41	8	Strong coverage
March	13.5°C	0.7°C	54 mm	5.4	11 h 50	35	Strong coverage
April	19°C	6.3°C	95 mm	8.3	13 h 09	55	Strong coverage
May	23.9°C	12.6°C	140 mm	10.1	14 h 15	74	Strong coverage
June	29.3°C	18.1°C	137 mm	8.4	14 h 51	58	Strong coverage
July	32.1°C	20.4°C	100 mm	7.5	14 h 37	50	Strong coverage
August	31.4°C	19.4°C	103 mm	7.6	13 h 40	54	Strong coverage
September	27.1°C	14.5°C	107 mm	7.1	12 h 23	75	Strong coverage
October	20.4°C	7.7°C	76 mm	6.4	11 h 07	66	Strong coverage
November	12.8°C	1.1°C	58 mm	4.2	10 h 01	34	Strong coverage
December	6.6°C	-3.9°C	38 mm	4.1	9 h 29	7	Strong coverage

What has changed

Pomona runs +1.3°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

+2.4

Feb

+1.7

Mar

+1.9

Apr

+0.2

May

+0.4

Jun

+1.9

Jul

+0.5

Aug

0.0

Sep

+1.6

Oct

+0.9

Nov

+1.0

Dec

+3.0

September daytime highs, 2011–2025. Last recorded: 27.2°C.

Records at POMONA LAKE, 1963–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	25.6°C29 Jan 2015	-26.1°C13 Jan 1974	49 mm3 Jan 1971	86 mm2021 · driest 0 mm in 2015	61
February	27.2°C23 Feb 2017	-28.9°C1 Feb 1979	60 mm9 Feb 2001	122 mm2001 · driest 0 mm in 2017	63
March	35.0°C22 Mar 2026	-21.7°C4 Mar 1978	80 mm18 Mar 1987	208 mm1973 · driest 9 mm in 2002	61
April	33.9°C14 Apr 2006	-10.6°C4 Apr 1975	91 mm28 Apr 1994	250 mm1999 · driest 4 mm in 1989	61
May	35.0°C20 May 2006	0.0°C3 May 2005	124 mm7 May 2007	363 mm2019 · driest 5 mm in 1966	64
June	42.2°C28 Jun 1980	6.1°C1 Jun 1982	130 mm4 Jun 1985	292 mm1969 · driest 20 mm in 2012	64
July	43.3°C11 Jul 1980	10.6°C6 Jul 1972	102 mm1 Jul 2007	251 mm1993 · driest 5 mm in 1975	62
August	44.4°C20 Aug 2023	8.9°C28 Aug 1986	105 mm31 Aug 2003	236 mm2019 · driest 9 mm in 2000	62
September	42.2°C3 Sep 2000	0.0°C23 Sep 1983	138 mm4 Sep 1965	303 mm1973 · driest 10 mm in 1968	61
October	35.0°C3 Oct 1963	-7.8°C31 Oct 1993	127 mm25 Oct 2023	189 mm1998 · driest 5 mm in 2015	60
November	30.0°C9 Nov 2006	-16.1°C29 Nov 1976	152 mm2 Nov 1998	181 mm1998 · driest 0 mm in 1989	63
December	23.3°C17 Dec 2021	-27.8°C23 Dec 1989	42 mm27 Dec 2015	92 mm2011 · driest 0 mm in 2001	63

Typical days per month at POMONA LAKE, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	25	<1	<1
February	<1	0	20	1	<1
March	2	<1	14	2	<1
April	6	<1	3	3	0
May	14	4	0	4	0
June	26	15	0	4	0
July	29	22	0	3	0
August	29	20	0	3	0
September	20	10	0	3	0
October	8	2	2	2	<1
November	<1	0	12	2	<1
December	0	0	23	1	<1

The best month has moved. On the 1961–1990 numbers the strongest month here was May (scoring 84); on 2011–2025 it is September (79). Both are scored the same way, from the same station — only the climate underneath changed.

How often, not how much — every day in POMONA LAKE’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%	12%	3%	5%	0.1–7.8°C
February	5%	13%	4%	8%	2.0–11.0°C
March	20%	19%	7%	18%	9.1–16.8°C
April	37%	27%	10%	30%	16.3–21.4°C
May	56%	31%	13%	38%	21.5–26.3°C
June	72%	28%	14%	33%	26.8–31.5°C
July	79%	22%	9%	19%	29.6–34.0°C
August	78%	23%	9%	24%	29.0–34.1°C
September	72%	23%	10%	22%	24.3–30.0°C
October	48%	20%	8%	21%	18.0–22.6°C
November	16%	15%	6%	10%	9.4–16.0°C
December	2%	13%	4%	7%	3.0–9.2°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.

1964Each stripe is one year’s mean temperature against the 52-year average. Warmest: 2012. Coolest: 1979.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4277555
NOAA station: USC00146498 · POMONA LAKE
Station distance: 11.2 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 28 usable years
Daylight: Calculated from latitude 38.60°, 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 POMONA LAKE is what differs

Overbrook→Pomona→Vassar→Williamsburg→Quenemo→Michigan Valley→

Or put two places side by side: Pomona vs Overbrook

Best time to visitPomona.