United States · 1991–2020

Best time to visit
Chesterton.

September leads for comfortable weather in Chesterton: typically 23.5°C by day, 13.4°C at night, with 95 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high23.5°C

Typical low13.4°C

Rain in September95 mm

Comfort

September

September · June · August

83climate match

Beach

July

July · August · June

71climate match

Outdoors

May

May · September · October

78climate match

The weakest month is January, scoring 5 against September’s 83 — days reach only 0°C, 24° 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

50° / -7.8°

Feb

51.9° / -6.1°

Mar

87.5° / -1.3°

Apr

3514.1° / 4.1°

May

6220.3° / 9.8°

Jun

7925.3° / 15.2°

Jul

7027.5° / 17.9°

Aug

7326.6° / 17.2°

Sep

8323.5° / 13.4°

Oct

4816.8° / 7°

Nov

189.4° / 1.4°

Dec

52.8° / -4.5°

Monthly climate evidence for Chesterton — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 26 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	0°C	-7.8°C	60 mm	8.5	3.2°C	9 h 28	5	Strong coverage
February	1.9°C	-6.1°C	49 mm	6.9	1.7°C	10 h 32	5	Strong coverage
March	7.5°C	-1.3°C	58 mm	8.4	1.8°C	11 h 48	8	Strong coverage
April	14.1°C	4.1°C	90 mm	9	4.0°C	13 h 16	35	Strong coverage
May	20.3°C	9.8°C	107 mm	9.8	7.9°C	14 h 30	62	Strong coverage
June	25.3°C	15.2°C	115 mm	9	15.1°C	15 h 10	79	Strong coverage
July	27.5°C	17.9°C	98 mm	7.5	21.3°C	14 h 55	70	Strong coverage
August	26.6°C	17.2°C	107 mm	8.2	22.6°C	13 h 51	73	Strong coverage
September	23.5°C	13.4°C	95 mm	7.2	20.2°C	12 h 25	83	Strong coverage
October	16.8°C	7°C	96 mm	8.8	14.7°C	11 h 01	48	Strong coverage
November	9.4°C	1.4°C	69 mm	7.7	9.5°C	9 h 47	18	Strong coverage
December	2.8°C	-4.5°C	52 mm	7.7	5.8°C	9 h 10	5	Strong coverage

Records at INDIANA DUNES NP, 1989–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	18.9°C8 Jan 2008	-29.4°C19 Jan 1994	84 mm8 Jan 2008	126 mm2005 · driest 2 mm in 2022	36
February	23.3°C28 Feb 2024	-26.1°C3 Feb 1996	47 mm21 Feb 1997	102 mm2009 · driest 10 mm in 2025	35
March	29.4°C22 Mar 2012	-20.0°C4 Mar 2002	67 mm1 Mar 2017	159 mm2017 · driest 13 mm in 2015	37
April	31.1°C16 Apr 2002	-7.8°C6 Apr 2018	52 mm25 Apr 2007	153 mm1993 · driest 20 mm in 2018	37
May	35.0°C29 May 2018	-1.1°C3 May 2023	145 mm10 May 1996	246 mm1996 · driest 25 mm in 1992	35
June	36.7°C29 Jun 2012	2.8°C5 Jun 1990	138 mm14 Jun 1994	332 mm1993 · driest 40 mm in 2005	36
July	38.9°C31 Jul 1999	7.2°C6 Jul 2001	107 mm18 Jul 1996	194 mm2003 · driest 1 mm in 2026	38
August	36.7°C3 Aug 1991	7.2°C27 Aug 2025	197 mm18 Aug 1990	313 mm1990 · driest 17 mm in 2019	37
September	35.6°C11 Sep 2013	1.7°C30 Sep 1993	121 mm13 Sep 2008	418 mm2008 · driest 15 mm in 2004	37
October	31.7°C2 Oct 2019	-5.0°C31 Oct 2023	94 mm26 Oct 2022	227 mm2001 · driest 0 mm in 2025	37
November	25.0°C2 Nov 2016	-13.9°C20 Nov 2022	98 mm28 Nov 1990	217 mm1990 · driest 8 mm in 1999	35
December	20.6°C6 Dec 2001	-28.3°C22 Dec 1989	41 mm7 Dec 1998	123 mm2008 · driest 3 mm in 2017	36

Typical days per month at INDIANA DUNES NP, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	27	2	8
February	0	0	24	1	5
March	<1	0	19	2	3
April	2	<1	5	3	<1
May	9	2	<1	3	0
June	17	6	0	4	0
July	22	9	0	3	0
August	20	6	0	3	0
September	12	3	0	2	0
October	3	<1	1	3	0
November	0	0	12	2	1
December	0	0	24	2	6

How often, not how much — every day in INDIANA DUNES NP’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%	27%	6%	30%	-2.4–3.2°C
February	<1%	24%	5%	26%	-0.7–5.4°C
March	6%	28%	6%	35%	4.6–12.0°C
April	16%	31%	10%	36%	11.7–16.9°C
May	36%	31%	9%	38%	17.9–22.7°C
June	59%	30%	12%	34%	23.9–26.8°C
July	74%	24%	8%	26%	25.6–29.5°C
August	73%	25%	10%	26%	25.0–28.2°C
September	59%	24%	8%	26%	21.6–25.8°C
October	24%	28%	10%	30%	15.1–18.9°C
November	5%	24%	7%	26%	6.6–12.7°C
December	0%	26%	5%	32%	-0.4–6.4°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.

1990Each stripe is one year’s mean temperature against the 31-year average. Warmest: 2025. Coolest: 2014.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4918962
NOAA station: USC00124244 · INDIANA DUNES NP
Station distance: 3.1 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 27 usable years
Daylight: Calculated from latitude 41.61°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 26 km from the place centre. A sheltered bay can run warmer than the open sea it is measured from.
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 INDIANA DUNES NP is what differs

Gary→Portage→Hobart→Lake Station→Porter→New Chicago→

Or put two places side by side: Chesterton vs Gary

Best time to visitChesterton.

September

July

May

The whole year,without the guesswork.

Nearby, measured,and named.

Best time to visit
Chesterton.

The whole year,
without the guesswork.

Nearby, measured,
and named.