United States · 1991–2020

Best time to visit
New Lenox.

September leads for comfortable weather in New Lenox: typically 24.7°C by day, 12.9°C at night, with 81 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high24.7°C

Typical low12.9°C

Rain in September81 mm

Comfort

September

September · June · August

85climate match

Beach

July

July · August · June

71climate match

Outdoors

October

October · May · September

73climate match

The weakest month is January, scoring 5 against September’s 85 — days reach only -0.3°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

5-0.3° / -8.8°

Feb

52.1° / -6.9°

Mar

128.6° / -1.6°

Apr

3915.7° / 3.9°

May

6621.9° / 9.7°

Jun

7527.1° / 15.4°

Jul

6328.9° / 17.8°

Aug

7027.9° / 17.2°

Sep

8524.7° / 12.9°

Oct

5217.5° / 6.2°

Nov

189.4° / 0°

Dec

52.6° / -5.4°

Monthly climate evidence for New Lenox — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	-0.3°C	-8.8°C	48 mm	7	9 h 29	5	Strong coverage
February	2.1°C	-6.9°C	46 mm	5.9	10 h 32	5	Strong coverage
March	8.6°C	-1.6°C	57 mm	7.2	11 h 48	12	Strong coverage
April	15.7°C	3.9°C	95 mm	9.2	13 h 16	39	Strong coverage
May	21.9°C	9.7°C	113 mm	9.9	14 h 30	66	Strong coverage
June	27.1°C	15.4°C	106 mm	8	15 h 10	75	Strong coverage
July	28.9°C	17.8°C	117 mm	7.7	14 h 54	63	Strong coverage
August	27.9°C	17.2°C	103 mm	7.4	13 h 50	70	Strong coverage
September	24.7°C	12.9°C	81 mm	6.1	12 h 25	85	Strong coverage
October	17.5°C	6.2°C	80 mm	7.4	11 h 01	52	Strong coverage
November	9.4°C	0°C	61 mm	6.9	9 h 47	18	Strong coverage
December	2.6°C	-5.4°C	50 mm	6.7	9 h 11	5	Strong coverage

Records at JOLIET BRANDON ROAD LOCK/DAM, 1975–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	18.3°C8 Jan 2008	-32.2°C20 Jan 1985	64 mm9 Jan 2026	92 mm2008 · driest 1 mm in 1981	50
February	22.8°C26 Feb 2000	-28.9°C6 Feb 1979	70 mm21 Feb 1997	142 mm1997 · driest 0 mm in 1987	51
March	30.0°C30 Mar 1986	-21.7°C4 Mar 2002	57 mm16 Mar 1984	144 mm2017 · driest 10 mm in 1987	51
April	33.3°C26 Apr 1986	-11.7°C7 Apr 1982	74 mm30 Apr 2017	173 mm2013 · driest 25 mm in 2012	51
May	35.0°C28 May 2018	-2.2°C10 May 2020	94 mm26 May 2011	203 mm2019 · driest 17 mm in 1992	50
June	40.0°C26 Jun 1988	1.7°C13 Jun 1985	130 mm13 Jun 1981	297 mm1993 · driest 10 mm in 1988	50
July	39.4°C14 Jul 1995	8.3°C6 Jul 1983	345 mm18 Jul 1996	441 mm1996 · driest 3 mm in 1991	51
August	38.9°C2 Aug 1988	3.9°C29 Aug 1986	98 mm24 Aug 2007	273 mm2007 · driest 12 mm in 1996	49
September	36.1°C9 Sep 1978	0.0°C23 Sep 1983	104 mm28 Sep 2019	295 mm2008 · driest 1 mm in 1979	51
October	31.1°C7 Oct 2007	-8.3°C29 Oct 1976	89 mm25 Oct 2021	214 mm1991 · driest 6 mm in 2005	50
November	25.6°C7 Nov 1975	-18.9°C26 Nov 1977	65 mm28 Nov 1990	208 mm1985 · driest 6 mm in 2021	50
December	21.1°C3 Dec 1982	-28.9°C25 Dec 1983	85 mm3 Dec 1982	185 mm1982 · driest 7 mm in 1995	51

Typical days per month at JOLIET BRANDON ROAD LOCK/DAM, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	28	1	4
February	0	0	25	2	3
March	<1	0	21	2	1
April	3	<1	6	3	<1
May	10	3	<1	4	0
June	21	9	0	4	0
July	27	13	0	4	0
August	26	9	0	4	0
September	16	5	0	3	0
October	5	<1	3	3	0
November	0	0	16	2	<1
December	0	0	26	2	3

How often, not how much — every day in JOLIET BRANDON ROAD LOCK/DAM’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%	21%	4%	20%	-4.3–2.4°C
February	<1%	21%	4%	20%	-3.7–5.8°C
March	5%	26%	7%	31%	5.0–11.9°C
April	19%	31%	11%	39%	13.3–18.5°C
May	46%	31%	11%	37%	19.5–25.0°C
June	71%	27%	12%	31%	25.7–28.6°C
July	74%	25%	11%	26%	27.5–30.9°C
August	75%	24%	10%	22%	26.4–29.6°C
September	68%	21%	8%	20%	23.1–26.7°C
October	28%	22%	8%	23%	15.8–19.7°C
November	5%	23%	6%	24%	5.8–12.4°C
December	0%	23%	6%	23%	-1.6–5.9°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.

1976Each stripe is one year’s mean temperature against the 44-year average. Warmest: 1998. Coolest: 2014.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4903535
NOAA station: USC00114530 · JOLIET BRANDON ROAD LOCK/DAM
Station distance: 11.5 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 29 usable years
Daylight: Calculated from latitude 41.51°, 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 JOLIET BRANDON ROAD LOCK/DAM is what differs

Joliet→Shorewood→Manhattan→Ingalls Park→Preston Heights→Elwood→

Or put two places side by side: New Lenox vs Joliet

Best time to visitNew Lenox.