United States · 1991–2020

Best time to visit
Hopatcong Hills.

September leads for comfortable weather in Hopatcong Hills: typically 24.1°C by day, 12°C at night, with 114 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high24.1°C

Typical low12°C

Rain in September114 mm

Comfort

September

September · June · August

79climate match

Beach

July

July · August · June

64climate match

Outdoors

May

May · September · October

74climate match

The weakest month is January, scoring 5 against September’s 79 — days reach only 2.4°C, 22° 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

52.4° / -7.2°

Feb

54.1° / -6.5°

Mar

69° / -2°

Apr

4116.1° / 3.8°

May

6721.8° / 9.5°

Jun

7526.2° / 14.3°

Jul

6128.9° / 17°

Aug

6827.7° / 16.1°

Sep

7924.1° / 12°

Oct

4517.3° / 5.9°

Nov

2211.4° / 0.7°

Dec

55.2° / -3.6°

Monthly climate evidence for Hopatcong Hills — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	2.4°C	-7.2°C	81 mm	8.2	9 h 32	5	Good coverage
February	4.1°C	-6.5°C	75 mm	8.2	10 h 34	5	Good coverage
March	9°C	-2°C	92 mm	9.1	11 h 49	6	Good coverage
April	16.1°C	3.8°C	92 mm	8.6	13 h 15	41	Good coverage
May	21.8°C	9.5°C	101 mm	10.2	14 h 27	67	Good coverage
June	26.2°C	14.3°C	111 mm	10	15 h 06	75	Good coverage
July	28.9°C	17°C	130 mm	9.9	14 h 50	61	Good coverage
August	27.7°C	16.1°C	126 mm	9.1	13 h 48	68	Good coverage
September	24.1°C	12°C	114 mm	7.6	12 h 25	79	Good coverage
October	17.3°C	5.9°C	120 mm	7.9	11 h 02	45	Good coverage
November	11.4°C	0.7°C	82 mm	7.3	9 h 50	22	Good coverage
December	5.2°C	-3.6°C	103 mm	9.4	9 h 15	5	Good coverage

Records at AEROFLEX-ANDOVER AP, 1998–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	20.6°C6 Jan 2007	-26.1°C24 Jan 2005	66 mm9 Jan 2024	155 mm2024 · driest 2 mm in 2025	28
February	25.0°C21 Feb 2018	-25.5°C24 Feb 2015	79 mm13 Feb 2008	195 mm2008 · driest 17 mm in 2002	27
March	26.1°C26 Mar 2021	-22.2°C7 Mar 2003	77 mm13 Mar 2010	182 mm2011 · driest 19 mm in 2016	27
April	33.3°C17 Apr 2002	-6.7°C7 Apr 2002	118 mm15 Apr 2007	201 mm2007 · driest 20 mm in 2021	26
May	35.0°C31 May 2022	-1.0°C9 May 2020	44 mm12 May 2019	254 mm2019 · driest 12 mm in 2023	28
June	36.7°C24 Jun 2025	3.3°C1 Jun 2001	72 mm23 Jun 2011	236 mm2003 · driest 29 mm in 1999	27
July	38.3°C22 Jul 2011	7.8°C2 Jul 2007	95 mm10 Jul 2010	496 mm2025 · driest 9 mm in 1999	28
August	37.2°C9 Aug 2001	7.2°C21 Aug 2000	134 mm28 Aug 2011	386 mm2011 · driest 35 mm in 2022	28
September	33.9°C4 Sep 2008	1.1°C29 Sep 2000	123 mm18 Sep 2004	418 mm2011 · driest 20 mm in 2007	28
October	33.3°C2 Oct 2019	-4.9°C19 Oct 2015	218 mm8 Oct 2005	437 mm2005 · driest 1 mm in 2024	28
November	26.1°C8 Nov 2020	-13.2°C23 Nov 2018	72 mm2 Nov 2018	259 mm2018 · driest 24 mm in 2017	27
December	22.8°C7 Dec 1998	-18.9°C14 Dec 2005	87 mm17 Dec 2000	218 mm2023 · driest 21 mm in 1998	28

Typical days per month at AEROFLEX-ANDOVER AP, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	0	0	27	3
February	0	0	26	2
March	<1	0	20	3
April	3	<1	7	3
May	9	2	<1	3
June	19	5	0	4
July	27	12	0	4
August	25	7	0	4
September	14	2	0	3
October	2	<1	4	3
November	<1	0	16	3
December	0	0	24	3

How often, not how much — every day in AEROFLEX-ANDOVER 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	<1%	27%	9%	32%	-0.1–5.5°C
February	<1%	29%	8%	35%	0.6–7.5°C
March	5%	30%	10%	36%	5.8–12.9°C
April	21%	30%	9%	44%	13.9–18.4°C
May	48%	33%	11%	44%	19.8–24.1°C
June	63%	36%	13%	43%	24.9–28.1°C
July	64%	36%	15%	43%	26.7–31.0°C
August	69%	31%	14%	32%	26.6–29.1°C
September	66%	27%	12%	30%	22.0–25.5°C
October	28%	25%	11%	27%	15.9–20.1°C
November	6%	24%	8%	25%	9.0–14.1°C
December	<1%	31%	11%	35%	2.2–8.4°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.

2000Each stripe is one year’s mean temperature against the 23-year average. Warmest: 2022. Coolest: 2000.2024

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5099292
NOAA station: USW00054779 · AEROFLEX-ANDOVER AP
Station distance: 9.1 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 21 usable years
Daylight: Calculated from latitude 40.94°, 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 AEROFLEX-ANDOVER AP is what differs

Sparta→Hopatcong→Lake Mohawk→Lake Hopatcong→Landing→Mount Arlington→

Or put two places side by side: Hopatcong Hills vs Sparta

Best time to visitHopatcong Hills.

September

July

May

The whole year,without the guesswork.

Nearby, measured,and named.

Best time to visit
Hopatcong Hills.

The whole year,
without the guesswork.

Nearby, measured,
and named.