United States · 1991–2020

Best time to visit
Big Coppitt Key.

January leads for comfortable weather in Big Coppitt Key: typically 24.2°C by day, 18°C at night, with 54 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortJanuary

Typical high24.2°C

Typical low18°C

Rain in January54 mm

Comfort

January

January · February · December

89climate match

Beach

March

March · April · November

90climate match

Outdoors

January

January · February · March

68climate match

The weakest month is September, scoring 26 against January’s 89 — days average 31.8°C, 8° above the 24°C the score treats as ideal, and nights stay at 26.2°C.

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

8924.2° / 18°

Feb

8725.4° / 19.2°

Mar

8126.5° / 20.4°

Apr

6828.3° / 22.5°

May

5530° / 24.5°

Jun

3931.6° / 26.1°

Jul

4032.3° / 26.7°

Aug

3232.6° / 26.8°

Sep

2631.8° / 26.2°

Oct

4430.1° / 24.9°

Nov

7327.4° / 22.1°

Dec

8225.7° / 20.1°

Monthly climate evidence for Big Coppitt Key — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 5 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	24.2°C	18°C	54 mm	5	23.0°C	10 h 46	89	Strong coverage
February	25.4°C	19.2°C	39 mm	3	22.9°C	11 h 18	87	Strong coverage
March	26.5°C	20.4°C	38 mm	3.5	23.7°C	11 h 57	81	Strong coverage
April	28.3°C	22.5°C	59 mm	3.7	25.2°C	12 h 42	68	Strong coverage
May	30°C	24.5°C	77 mm	5.1	26.9°C	13 h 19	55	Strong coverage
June	31.6°C	26.1°C	120 mm	7.7	28.6°C	13 h 39	39	Strong coverage
July	32.3°C	26.7°C	85 mm	8.4	29.5°C	13 h 31	40	Strong coverage
August	32.6°C	26.8°C	124 mm	10	30.0°C	12 h 59	32	Strong coverage
September	31.8°C	26.2°C	177 mm	12.1	29.5°C	12 h 16	26	Good coverage
October	30.1°C	24.9°C	127 mm	8.9	28.1°C	11 h 32	44	Strong coverage
November	27.4°C	22.1°C	52 mm	4	25.8°C	10 h 55	73	Strong coverage
December	25.7°C	20.1°C	51 mm	4.5	24.2°C	10 h 37	82	Strong coverage

What has changed

Big Coppitt Key runs +1.8°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

+1.7

Feb

+3.1

Mar

+1.9

Apr

+1.9

May

+1.6

Jun

+1.5

Jul

+1.6

Aug

+1.7

Sep

+1.4

Oct

+1.7

Nov

+1.9

Dec

+2.2

January daytime highs, 2011–2025. Last recorded: 24.0°C.

Records at KEY WEST NAS, 1945–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	32.2°C3 Jan 2023	6.1°C13 Jan 1981	183 mm22 Jan 1983	426 mm1983 · driest 0 mm in 1968	71
February	33.3°C23 Feb 2023	6.7°C5 Feb 1996	114 mm18 Feb 1981	166 mm1998 · driest 0 mm in 2026	72
March	33.9°C3 Mar 2022	8.3°C4 Mar 1980	102 mm29 Mar 2025	192 mm1987 · driest 0 mm in 1956	73
April	32.8°C27 Apr 2003	12.2°C2 Apr 1987	160 mm12 Apr 1985	235 mm1985 · driest 0 mm in 2003	71
May	35.6°C22 May 2025	15.0°C20 May 2021	144 mm30 May 1960	327 mm1988 · driest 0 mm in 2009	72
June	37.2°C30 Jun 1998	20.0°C7 Jun 1966	172 mm25 Jun 1992	442 mm1992 · driest 0 mm in 2009	69
July	37.8°C29 Jul 2024	21.1°C24 Jul 1970	116 mm29 Jul 1983	285 mm1980 · driest 2 mm in 2008	71
August	38.9°C13 Aug 2024	17.8°C15 Aug 1997	270 mm26 Aug 2005	742 mm2005 · driest 0 mm in 2015	70
September	39.4°C22 Sep 2017	18.9°C14 Sep 1996	168 mm12 Sep 2020	446 mm1994 · driest 26 mm in 2008	70
October	34.4°C11 Oct 2022	15.6°C28 Oct 1957	188 mm17 Oct 2011	541 mm2011 · driest 0 mm in 2022	72
November	35.6°C1 Nov 2020	10.0°C25 Nov 1970	241 mm1 Nov 2005	252 mm2005 · driest 0 mm in 2025	71
December	32.2°C20 Dec 2007	6.1°C24 Dec 1989	144 mm8 Dec 1987	250 mm1986 · driest 0 mm in 2005	71

Typical days per month at KEY WEST NAS, 1991–2020
Month	Days 25°C+	Days 30°C+	Heavy rain (10 mm+)
January	16	0	1
February	18	<1	1
March	24	1	1
April	28	7	1
May	30	18	2
June	29	27	3
July	31	30	3
August	30	30	3
September	29	27	5
October	29	19	4
November	24	5	<1
December	20	<1	1

How often, not how much — every day in KEY WEST NAS’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	72%	15%	4%	10%	21.9–26.4°C
February	78%	13%	5%	8%	22.3–27.2°C
March	85%	11%	4%	4%	24.2–28.0°C
April	89%	11%	4%	7%	26.3–29.6°C
May	82%	19%	8%	21%	28.3–31.2°C
June	71%	29%	11%	33%	30.0–32.7°C
July	72%	28%	9%	35%	30.9–33.2°C
August	64%	36%	12%	50%	31.2–33.7°C
September	59%	41%	16%	58%	30.4–32.6°C
October	72%	28%	10%	32%	28.1–31.1°C
November	85%	15%	4%	10%	25.0–28.6°C
December	78%	14%	4%	11%	22.3–26.9°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.

1954Each stripe is one year’s mean temperature against the 57-year average. Warmest: 2022. Coolest: 1981.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4147679
NOAA station: USW00012850 · KEY WEST NAS
Station distance: 2.8 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 24 usable years
Daylight: Calculated from latitude 24.60°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 5 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 KEY WEST NAS is what differs

Cudjoe Key→Bay Point→El Chico→Perky→Pirates Cove→Sugarloaf Shores→

Or put two places side by side: Big Coppitt Key vs Cudjoe Key

Best time to visitBig Coppitt Key.

January

March

January

The whole year,without the guesswork.

Big Coppitt Key runs +1.8°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
Big Coppitt Key.

The whole year,
without the guesswork.

Big Coppitt Key runs +1.8°C
on the 1961–1990 baseline.

Nearby, measured,
and named.