United States · 1991–2020

Best time to visit
Heidelberg.

June leads for comfortable weather in Heidelberg: typically 25.4°C by day, 13.7°C at night, with 128 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortJune

Typical high25.4°C

Typical low13.7°C

Rain in June128 mm

Comfort

June

June · August · September

75climate match

Beach

July

July · August · June

65climate match

Outdoors

September

September · May · October

81climate match

The weakest month is January, scoring 5 against June’s 75 — days reach only -5°C, 29° 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

5-5° / -14.8°

Feb

5-2.7° / -12.9°

Mar

54.5° / -5.8°

Apr

3013.1° / 1.1°

May

5720.2° / 8.1°

Jun

7525.4° / 13.7°

Jul

7327.4° / 16.1°

Aug

7526° / 14.5°

Sep

7522.2° / 9.9°

Oct

4014.6° / 3°

Nov

55.3° / -4.2°

Dec

5-2.1° / -11.2°

Monthly climate evidence for Heidelberg — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	-5°C	-14.8°C	20 mm	3.5	9 h 11	5	Strong coverage
February	-2.7°C	-12.9°C	21 mm	3.2	10 h 22	5	Strong coverage
March	4.5°C	-5.8°C	45 mm	5.2	11 h 46	5	Strong coverage
April	13.1°C	1.1°C	75 mm	6.9	13 h 24	30	Strong coverage
May	20.2°C	8.1°C	119 mm	9.4	14 h 46	57	Strong coverage
June	25.4°C	13.7°C	128 mm	8.9	15 h 31	75	Strong coverage
July	27.4°C	16.1°C	100 mm	7.8	15 h 14	73	Strong coverage
August	26°C	14.5°C	127 mm	7.8	14 h 02	75	Strong coverage
September	22.2°C	9.9°C	79 mm	6.6	12 h 28	75	Strong coverage
October	14.6°C	3°C	66 mm	6.2	10 h 54	40	Strong coverage
November	5.3°C	-4.2°C	39 mm	4	9 h 32	5	Strong coverage
December	-2.1°C	-11.2°C	31 mm	4.6	8 h 51	5	Strong coverage

What has changed

Heidelberg runs -0.1°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

+0.6

Feb

-1.0

Mar

+0.6

Apr

-2.3

May

-1.3

Jun

-0.4

Jul

-0.7

Aug

-0.6

Sep

+1.7

Oct

-0.3

Nov

+0.6

Dec

+1.6

June daytime highs, 2011–2025. Last recorded: 25.0°C.

Records at JORDAN 1SSW, 1943–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	15.0°C24 Jan 1981	-40.6°C19 Jan 1970	58 mm18 Jan 1996	102 mm1996 · driest 0 mm in 2008	81
February	18.3°C27 Feb 2024	-37.8°C3 Feb 1989	43 mm29 Feb 2012	64 mm2023 · driest 0 mm in 1993	81
March	27.8°C30 Mar 1968	-36.7°C11 Mar 1948	64 mm1 Mar 2007	112 mm2007 · driest 4 mm in 1997	81
April	33.9°C21 Apr 1980	-16.1°C5 Apr 2018	55 mm1 Apr 2023	191 mm2014 · driest 3 mm in 1987	81
May	37.2°C29 May 2018	-7.8°C6 May 1989	145 mm21 May 1960	282 mm2012 · driest 13 mm in 1988	81
June	38.9°C24 Jun 1988	-1.1°C3 Jun 1945	106 mm26 Jun 1998	302 mm1956 · driest 7 mm in 1988	79
July	40.6°C31 Jul 1988	3.9°C1 Jul 1988	105 mm2 Jul 1992	225 mm1955 · driest 25 mm in 1980	80
August	38.3°C1 Aug 1988	0.6°C29 Aug 1988	127 mm31 Aug 1993	276 mm1993 · driest 10 mm in 1969	79
September	35.0°C7 Sep 1976	-10.0°C26 Sep 2000	153 mm15 Sep 1992	176 mm1946 · driest 4 mm in 2024	81
October	32.2°C3 Oct 1997	-16.1°C30 Oct 1988	69 mm17 Oct 1996	148 mm2009 · driest 0 mm in 1952	79
November	25.0°C4 Nov 2020	-28.9°C26 Nov 1977	68 mm20 Nov 1973	127 mm1996 · driest 0 mm in 2002	79
December	19.4°C1 Dec 1998	-40.6°C19 Dec 1983	33 mm12 Dec 2010	87 mm2010 · driest 0 mm in 1943	80

Typical days per month at JORDAN 1SSW, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	29	<1	4
February	0	0	27	<1	3
March	<1	0	25	2	2
April	1	<1	12	3	<1
May	7	2	2	4	0
June	17	5	0	4	0
July	24	7	0	3	0
August	21	4	0	4	0
September	10	2	<1	2	0
October	2	<1	10	2	<1
November	<1	0	22	1	1
December	0	0	29	<1	3

The best month has moved. On the 1961–1990 numbers the strongest month here was August (scoring 79); on 2011–2025 it is September (88). Both are scored the same way, from the same station — only the climate underneath changed.

How often, not how much — every day in JORDAN 1SSW’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%	12%	1%	6%	-8.6–-1.0°C
February	0%	12%	2%	7%	-6.0–2.2°C
March	2%	18%	5%	15%	0.0–8.4°C
April	17%	23%	8%	25%	9.9–17.0°C
May	43%	30%	11%	37%	18.6–23.6°C
June	66%	31%	12%	38%	24.1–27.7°C
July	74%	25%	10%	26%	26.0–30.2°C
August	73%	25%	11%	26%	24.8–28.2°C
September	54%	23%	8%	25%	20.3–24.2°C
October	22%	18%	6%	16%	12.7–17.9°C
November	2%	15%	4%	10%	0.9–8.8°C
December	0%	14%	2%	8%	-6.2–1.1°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 73-year average. Warmest: 2012. Coolest: 1989.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5029784
NOAA station: USC00214176 · JORDAN 1SSW
Station distance: 17.7 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 27 usable years
Daylight: Calculated from latitude 44.49°, 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 JORDAN 1SSW is what differs

New Prague→Belle Plaine→Jordan→Montgomery→Hamburg→Assumption→

Or put two places side by side: Heidelberg vs New Prague

Best time to visitHeidelberg.

June

July

September

The whole year,without the guesswork.

Heidelberg runs -0.1°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
Heidelberg.

The whole year,
without the guesswork.

Heidelberg runs -0.1°C
on the 1961–1990 baseline.

Nearby, measured,
and named.