United States · 1991–2020

Best time to visit
Sayville.

September leads for comfortable weather in Sayville: typically 23.9°C by day, 14.8°C at night, with 92 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high23.9°C

Typical low14.8°C

Rain in September92 mm

Comfort

September

September · June · August

88climate match

Beach

July

July · August · June

81climate match

Outdoors

May

May · October · September

83climate match

The weakest month is January, scoring 5 against September’s 88 — days reach only 4.1°C, 20° 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

54.1° / -4.3°

Feb

55.1° / -3.8°

Mar

68.9° / -0.2°

Apr

3714.8° / 4.9°

May

6720.3° / 10.3°

Jun

8125.3° / 15.9°

Jul

6728.4° / 19.4°

Aug

6827.6° / 18.7°

Sep

8823.9° / 14.8°

Oct

5518° / 8.3°

Nov

2812.2° / 2.9°

Dec

57° / -1.4°

Monthly climate evidence for Sayville — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 13 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	4.1°C	-4.3°C	93 mm	8.9	6.1°C	9 h 33	5	Strong coverage
February	5.1°C	-3.8°C	85 mm	8.2	4.3°C	10 h 35	5	Strong coverage
March	8.9°C	-0.2°C	115 mm	9.1	4.6°C	11 h 49	6	Strong coverage
April	14.8°C	4.9°C	103 mm	8.8	7.4°C	13 h 14	37	Strong coverage
May	20.3°C	10.3°C	83 mm	9.1	12.1°C	14 h 26	67	Strong coverage
June	25.3°C	15.9°C	102 mm	7.9	17.7°C	15 h 04	81	Strong coverage
July	28.4°C	19.4°C	83 mm	7.5	22.0°C	14 h 49	67	Strong coverage
August	27.6°C	18.7°C	108 mm	6.9	22.6°C	13 h 47	68	Strong coverage
September	23.9°C	14.8°C	92 mm	7	20.9°C	12 h 25	88	Strong coverage
October	18°C	8.3°C	101 mm	6.9	17.2°C	11 h 03	55	Strong coverage
November	12.2°C	2.9°C	87 mm	7.7	13.0°C	9 h 51	28	Strong coverage
December	7°C	-1.4°C	118 mm	9.7	9.3°C	9 h 16	5	Strong coverage

What has changed

Sayville runs +1.5°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

+1.6

Feb

+2.0

Mar

+1.4

Apr

+1.3

May

+1.2

Jun

+1.3

Jul

+1.9

Aug

+1.3

Sep

+1.8

Oct

+1.6

Nov

+0.8

Dec

+2.1

September daytime highs, 2011–2025. Last recorded: 25.6°C.

Records at ISLIP-LI MACARTHUR AP, 1963–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	20.6°C29 Jan 2002	-22.2°C18 Jan 1965	92 mm3 Jan 1999	262 mm1979 · driest 13 mm in 1970	63
February	21.7°C16 Feb 2023	-25.6°C13 Feb 1967	62 mm25 Feb 2010	158 mm2008 · driest 22 mm in 1980	63
March	27.8°C13 Mar 1990	-17.8°C18 Mar 1967	83 mm9 Mar 1998	242 mm2024 · driest 25 mm in 2012	63
April	34.4°C17 Apr 2002	-8.9°C1 Apr 1969	118 mm23 Apr 2006	231 mm1983 · driest 25 mm in 1978	63
May	36.7°C20 May 1996	0.0°C1 May 2008	102 mm16 May 1989	258 mm1989 · driest 11 mm in 2015	63
June	38.3°C24 Jun 2025	5.6°C12 Jun 1972	124 mm6 Jun 2000	275 mm2003 · driest 15 mm in 1988	63
July	40.0°C3 Jul 1966	9.4°C2 Jul 1965	118 mm16 Jul 2023	212 mm1984 · driest 15 mm in 1966	63
August	37.8°C2 Aug 1975	7.2°C30 Aug 1986	343 mm13 Aug 2014	357 mm2014 · driest 5 mm in 1964	62
September	34.4°C3 Sep 1973	3.3°C20 Sep 1979	79 mm15 Sep 1966	191 mm1966 · driest 6 mm in 2024	63
October	31.7°C2 Oct 2019	-5.0°C31 Oct 1966	137 mm14 Oct 2005	357 mm2005 · driest 3 mm in 2024	63
November	26.7°C7 Nov 2022	-11.7°C24 Nov 1989	67 mm20 Nov 1988	214 mm2018 · driest 10 mm in 1976	63
December	25.0°C7 Dec 1998	-18.3°C31 Dec 1963	77 mm28 Dec 2023	227 mm1996 · driest 23 mm in 1985	63

Typical days per month at ISLIP-LI MACARTHUR AP, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	25	3	4
February	0	0	23	3	4
March	<1	0	17	4	3
April	<1	<1	3	3	<1
May	5	1	0	3	0
June	17	4	0	3	0
July	27	10	0	3	0
August	27	7	0	3	0
September	13	1	0	3	0
October	2	<1	<1	3	0
November	0	0	9	3	<1
December	0	0	21	4	3

The best month has moved. On the 1961–1990 numbers the strongest month here was June (scoring 90); on 2011–2025 it is September (90). Both are scored the same way, from the same station — only the climate underneath changed.

How often, not how much — every day in ISLIP-LI MACARTHUR 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%	28%	10%	31%	0.7–6.9°C
February	<1%	28%	10%	33%	1.8–7.8°C
March	2%	28%	11%	33%	6.5–11.4°C
April	12%	28%	10%	33%	12.5–16.2°C
May	40%	29%	9%	34%	17.8–21.6°C
June	70%	26%	9%	25%	23.3–26.7°C
July	77%	23%	8%	19%	26.1–29.6°C
August	77%	22%	9%	20%	25.7–28.9°C
September	68%	22%	9%	19%	22.1–25.1°C
October	28%	21%	9%	18%	16.1–20.2°C
November	3%	26%	11%	29%	10.5–14.3°C
December	<1%	31%	12%	37%	3.7–9.4°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.

1964Each stripe is one year’s mean temperature against the 62-year average. Warmest: 2023. Coolest: 1968.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5136421
NOAA station: USW00004781 · ISLIP-LI MACARTHUR AP
Station distance: 6.7 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 30 usable years
Daylight: Calculated from latitude 40.74°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 13 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 ISLIP-LI MACARTHUR AP is what differs

Brentwood→Central Islip→Centereach→Holbrook→Smithtown→Bay Shore→

Or put two places side by side: Sayville vs Brentwood

Best time to visitSayville.

September

July

May

The whole year,without the guesswork.

Sayville runs +1.5°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
Sayville.

The whole year,
without the guesswork.

Sayville runs +1.5°C
on the 1961–1990 baseline.

Nearby, measured,
and named.