United States · 1991–2020

Best time to visit
Denver.

September leads for comfortable weather in Denver: typically 24.3°C by day, 10.6°C at night, with 80 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high24.3°C

Typical low10.6°C

Rain in September80 mm

Comfort

September

September · August · June

81climate match

Beach

July

July · August · June

71climate match

Outdoors

September

September · May · October

73climate match

The weakest month is January, scoring 5 against September’s 81 — days reach only -2.7°C, 27° 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

5-2.7° / -12.6°

Feb

5-0.3° / -10.1°

Mar

67.4° / -3.5°

Apr

3415.4° / 2.6°

May

6522° / 9.4°

Jun

6727.3° / 15.3°

Jul

6628.8° / 17°

Aug

7427.6° / 15.4°

Sep

8124.3° / 10.6°

Oct

4716.6° / 3.9°

Nov

107.8° / -3.1°

Dec

50.3° / -9°

Monthly climate evidence for Denver — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	-2.7°C	-12.6°C	28 mm	5.6	9 h 22	5	Strong coverage
February	-0.3°C	-10.1°C	29 mm	5.5	10 h 28	5	Strong coverage
March	7.4°C	-3.5°C	50 mm	7.3	11 h 48	6	Strong coverage
April	15.4°C	2.6°C	103 mm	9	13 h 19	34	Strong coverage
May	22°C	9.4°C	117 mm	10.2	14 h 36	65	Strong coverage
June	27.3°C	15.3°C	145 mm	9.8	15 h 18	67	Strong coverage
July	28.8°C	17°C	110 mm	7.3	15 h 01	66	Strong coverage
August	27.6°C	15.4°C	106 mm	7.1	13 h 55	74	Strong coverage
September	24.3°C	10.6°C	80 mm	6.9	12 h 26	81	Strong coverage
October	16.6°C	3.9°C	70 mm	6.5	10 h 58	47	Strong coverage
November	7.8°C	-3.1°C	47 mm	5.8	9 h 41	10	Strong coverage
December	0.3°C	-9°C	37 mm	5.7	9 h 03	5	Strong coverage

What has changed

Denver runs +1.6°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

+1.2

Mar

+2.5

Apr

+0.5

May

+0.9

Jun

+1.3

Jul

+0.6

Aug

+0.8

Sep

+2.6

Oct

+1.1

Nov

+1.4

Dec

+3.5

September daytime highs, 2011–2025. Last recorded: 26.9°C.

Records at WATERLOO MUNI AP, 1950–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	18.3°C26 Jan 2002	-36.7°C16 Jan 2009	51 mm22 Jan 2018	73 mm2017 · driest 3 mm in 1951	76
February	25.6°C26 Feb 2024	-35.0°C2 Feb 1996	34 mm22 Feb 1981	90 mm1971 · driest 1 mm in 1969	76
March	30.6°C21 Mar 2026	-36.7°C1 Mar 1962	50 mm30 Mar 1998	138 mm1961 · driest 4 mm in 1994	77
April	37.8°C22 Apr 1980	-20.0°C6 Apr 1982	78 mm25 Apr 2008	274 mm2008 · driest 12 mm in 2021	77
May	36.1°C27 May 2018	-5.6°C3 May 2005	87 mm29 May 1980	275 mm2013 · driest 21 mm in 1992	77
June	39.4°C21 Jun 1988	3.3°C1 Jun 1964	111 mm15 Jun 1980	257 mm1993 · driest 22 mm in 1955	76
July	40.6°C31 Jul 1988	5.6°C7 Jul 1984	139 mm2 Jul 1999	326 mm1999 · driest 8 mm in 1998	77
August	40.6°C23 Aug 2023	0.6°C20 Aug 1950	125 mm20 Aug 1966	268 mm1998 · driest 5 mm in 2003	76
September	37.8°C3 Sep 2023	-5.6°C29 Sep 1967	82 mm1 Sep 2018	339 mm2018 · driest 11 mm in 1953	76
October	35.0°C3 Oct 1997	-11.7°C30 Oct 1988	75 mm22 Oct 2020	149 mm2009 · driest 0 mm in 1952	76
November	26.7°C8 Nov 1999	-27.2°C26 Nov 1977	61 mm4 Nov 1959	143 mm1992 · driest 0 mm in 1954	76
December	23.3°C15 Dec 2021	-33.9°C25 Dec 2000	84 mm13 Dec 2015	150 mm2015 · driest 4 mm in 2002	76

Typical days per month at WATERLOO MUNI AP, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	30	<1	7
February	0	0	27	<1	6
March	<1	0	23	2	3
April	3	<1	10	3	1
May	11	2	1	4	<1
June	23	9	0	5	0
July	28	12	0	4	0
August	25	8	0	3	0
September	15	5	<1	3	0
October	3	<1	9	2	<1
November	<1	0	22	2	3
December	0	0	29	1	6

The best month has moved. On the 1961–1990 numbers the strongest month here was August (scoring 80); on 2011–2025 it is September (83). Both are scored the same way, from the same station — only the climate underneath changed.

How often, not how much — every day in WATERLOO MUNI 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	0%	16%	2%	10%	-8.1–-0.4°C
February	<1%	16%	2%	14%	-4.9–4.2°C
March	5%	23%	6%	23%	2.2–10.5°C
April	20%	29%	10%	36%	12.2–18.0°C
May	47%	31%	12%	39%	19.2–24.4°C
June	68%	30%	14%	37%	25.5–29.3°C
July	74%	25%	12%	25%	27.1–31.0°C
August	76%	23%	10%	23%	26.0–29.9°C
September	63%	22%	8%	22%	21.4–26.6°C
October	28%	20%	7%	19%	13.9–19.5°C
November	4%	18%	5%	15%	3.5–10.8°C
December	0%	17%	3%	13%	-4.3–4.2°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.

1951Each stripe is one year’s mean temperature against the 75-year average. Warmest: 2024. Coolest: 1972.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4853799
NOAA station: USW00094910 · WATERLOO MUNI AP
Station distance: 14 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 30 usable years
Daylight: Calculated from latitude 42.67°, 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 WATERLOO MUNI AP is what differs

Waterloo→Cedar Falls→Waverly→Evansdale→Hudson→Elk Run Heights→

Or put two places side by side: Denver vs Waterloo

Best time to visitDenver.

September

July

September

The whole year,without the guesswork.

Denver runs +1.6°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
Denver.

The whole year,
without the guesswork.

Denver runs +1.6°C
on the 1961–1990 baseline.

Nearby, measured,
and named.