United States · 1991–2020

Best time to visit
Riverside.

September leads for comfortable weather in Riverside: typically 26.6°C by day, 14.2°C at night, with 76 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high26.6°C

Typical low14.2°C

Rain in September76 mm

Comfort

September

September · May · August

81climate match

Beach

August

August · July · June

77climate match

Outdoors

October

October · April · September

82climate match

The weakest month is January, scoring 5 against September’s 81 — days reach only 2.7°C, 21° 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

52.7° / -5.8°

Feb

55.3° / -4°

Mar

1610.7° / 0°

Apr

4718.3° / 6°

May

7624.2° / 12.5°

Jun

6129° / 17.8°

Jul

5530.8° / 19.8°

Aug

6330.3° / 18.6°

Sep

8126.6° / 14.2°

Oct

6119.3° / 7.3°

Nov

2511.6° / 1.5°

Dec

55.2° / -2.8°

Monthly climate evidence for Riverside — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	2.7°C	-5.8°C	80 mm	9.1	9 h 38	5	Strong coverage
February	5.3°C	-4°C	60 mm	7.4	10 h 38	5	Strong coverage
March	10.7°C	0°C	90 mm	9.1	11 h 49	16	Strong coverage
April	18.3°C	6°C	113 mm	10.5	13 h 12	47	Strong coverage
May	24.2°C	12.5°C	116 mm	11	14 h 21	76	Strong coverage
June	29°C	17.8°C	116 mm	10.3	14 h 58	61	Strong coverage
July	30.8°C	19.8°C	103 mm	8.6	14 h 43	55	Strong coverage
August	30.3°C	18.6°C	79 mm	7.1	13 h 44	63	Strong coverage
September	26.6°C	14.2°C	76 mm	6.5	12 h 24	81	Strong coverage
October	19.3°C	7.3°C	76 mm	7.1	11 h 05	61	Strong coverage
November	11.6°C	1.5°C	77 mm	7.6	9 h 56	25	Strong coverage
December	5.2°C	-2.8°C	78 mm	8.4	9 h 22	5	Strong coverage

What has changed

Riverside runs +1.0°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

+1.2

Feb

+1.7

Mar

+1.1

Apr

+1.3

May

+1.5

Jun

+0.9

Jul

+0.4

Aug

+0.9

Sep

+1.3

Oct

+0.4

Nov

-0.5

Dec

+1.5

September daytime highs, 2011–2020. Last recorded: 29.4°C.

Records at DAYTON MCD, 1893–2021
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	23.9°C21 Jan 1906	-29.4°C20 Jan 1985	74 mm22 Jan 1959	298 mm1937 · driest 7 mm in 1981	118
February	25.0°C26 Feb 2000	-33.3°C13 Feb 1899	58 mm2 Feb 1988	172 mm1909 · driest 5 mm in 1968	114
March	31.1°C22 Mar 2012	-17.8°C6 Mar 1901	83 mm5 Mar 1897	263 mm1913 · driest 1 mm in 1910	117
April	32.2°C30 Apr 1899	-9.4°C1 Apr 1923	80 mm14 Apr 1922	278 mm2011 · driest 8 mm in 1962	118
May	36.7°C28 May 1911	-2.2°C11 May 1913	99 mm18 May 1991	247 mm1968 · driest 6 mm in 1965	118
June	39.4°C19 Jun 1994	2.8°C10 Jun 1913	106 mm19 Jun 2021	241 mm2021 · driest 8 mm in 1962	117
July	42.2°C22 Jul 1901	7.2°C11 Jul 1898	70 mm22 Jul 2006	227 mm1992 · driest 11 mm in 1916	117
August	40.6°C5 Aug 1918	2.8°C31 Aug 1915	84 mm15 Aug 1905	226 mm1905 · driest 4 mm in 1967	118
September	38.9°C5 Sep 1899	-1.7°C23 Sep 1913	118 mm14 Sep 1979	214 mm2002 · driest 0 mm in 2007	118
October	36.7°C3 Oct 2019	-7.8°C30 Oct 1895	97 mm5 Oct 1910	193 mm1919 · driest 3 mm in 1963	119
November	27.2°C2 Nov 1999	-15.6°C30 Nov 1958	79 mm6 Nov 1948	244 mm1985 · driest 10 mm in 1917	119
December	23.9°C7 Dec 1998	-26.7°C23 Dec 1989	70 mm22 Dec 2013	220 mm1990 · driest 10 mm in 1976	117

Typical days per month at DAYTON MCD, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	25	3	4
February	<1	0	22	2	3
March	1	<1	17	3	1
April	5	<1	4	4	<1
May	15	6	<1	4	0
June	25	14	0	4	0
July	29	19	0	4	0
August	29	18	0	3	0
September	19	9	0	2	0
October	7	1	2	3	<1
November	<1	0	13	3	<1
December	0	0	22	3	2

The best month has moved. On the 1961–1990 numbers the strongest month here was September (scoring 87); on 2011–2025 it is May (85). Both are scored the same way, from the same station — only the climate underneath changed.

How often, not how much — every day in DAYTON MCD’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%	29%	8%	34%	-0.9–6.5°C
February	<1%	28%	8%	33%	1.0–7.8°C
March	8%	32%	10%	38%	7.2–14.4°C
April	27%	34%	11%	43%	14.6–20.5°C
May	53%	33%	12%	44%	20.7–27.1°C
June	67%	31%	12%	36%	26.4–30.8°C
July	73%	28%	11%	29%	29.0–32.9°C
August	76%	24%	9%	23%	28.1–31.7°C
September	71%	21%	8%	19%	23.9–28.6°C
October	39%	23%	7%	23%	16.8–21.9°C
November	7%	28%	9%	31%	8.3–14.0°C
December	<1%	28%	8%	32%	1.4–8.0°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.

1896Each stripe is one year’s mean temperature against the 106-year average. Warmest: 1998. Coolest: 1917.2019

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4522586
NOAA station: USC00332067 · DAYTON MCD
Station distance: 5.7 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 28 usable years
Daylight: Calculated from latitude 39.78°, 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 DAYTON MCD is what differs

Dayton→Kettering→Beavercreek→Huber Heights→Fairborn→Trotwood→

Or put two places side by side: Riverside vs Dayton

Best time to visitRiverside.