Islip, NY: September

30 September 2026: September 2026 averaged 67.4°F in Islip, NY, the warmest September since 2025, tied 17th warmest of 63 (with 2014).

September 2026

Mean temperature: 67.4°F; Warmest since 2025; 17th warmest of 63
Precipitation: 8.76 in; Wettest on record; Wettest of 63, provisional

A normal September in Islip, NY (1991 to 2020): a mean temperature of 66.9°F, between 64.5°F and 69.1°F in eight years of ten and 3.72 in of precipitation, between 1.41 in and 5.72 in in eight years of ten.

The mean temperature of every September in Islip, NY since 1964: 67.4°F in 2026; the highest is 70.9°F, in 2015.

Normal range, 64.5 to 69.1°F

Every year, ranked, as a table

Every September in Islip, NY from 1963 to 2026, ranked: the mean temperature, the mean high and the mean low from the warmest, the precipitation from the wettest; a year missing more than a tenth of its days is not ranked.

Year	Mean, °F	Rank	High, °F	Rank	Low, °F	Rank	Precipitation, in	Rank	Days missing
2026	67.4	17	74.1	36	60.6	11	8.76	1	0
2025	69.8	3	78.1	4	61.4	7	1.58	51	0
2024	66.8	27	75	26	58.6	24	0.24	63	0
2023	68.6	10	75.5	17	61.6	5	6.78	4	0
2022	68.2	13	76.9	8	59.5	15	2.89	38	0
2021	69.6	5	77.2	6	62	2	5.22	11	0
2020	67	22	75.4	18	58.6	24	3.87	27	0
2019	67.1	21	76.3	12	57.9	33	0.61	62	0
2018	69.8	3	76	13	63.6	1	5.04	13	0
2017	69	7	77.2	6	60.7	9	3.99	26	0
2016	68.9	9	76.4	10	61.4	7	3.05	37	0
2015	70.9	1	80.1	1	61.6	5	4.03	25	0
2014	67.4	17	75.4	18	59.4	19	1.62	50	0
2013	64.7	46	74.2	35	55.2	59	1.83	46	0
2012	66.3	31	74.5	30	58.1	31	3.56	30	0
2011	69	7	76	13	62	2	4.27	21	0
2010	68.3	12	76.4	10	60.3	14	2.11	44	0
2009	64.3	52	73.1	45	55.6	57	2.65	39	0
2008	67.7	16	75.1	23	60.4	13	7.46	3	0
2007	67.2	20	76	13	58.4	27	1.31	55	0
2006	64.4	50	72.4	51	56.3	47	4.29	20	0
2005	70.2	2	79.8	2	60.5	12	1.31	55	0
2004	66.5	29	74.9	27	58.1	31	6.37	7	0
2003	66.9	24	74.4	33	59.5	15	3.49	32	0
2002	67.3	19	75.4	18	59.2	20	4.59	16	0
2001	65.1	41	74	37	56.1	50	2.33	42	0
2000	64.5	49	73.3	42	55.7	54	4.82	14	0
1999	66.9	24	74.9	27	58.9	22	5.65	9	0
1998	68.6	10	77.7	5	59.5	15	2.28	43	0
1997	65.9	33	74.5	30	57.2	39	1.42	54	0
1996	66.4	30	74.5	30	58.3	28	6.41	6	0
1995	65.2	39	73.6	39	56.8	42	4.74	15	0
1994	65	43	73.6	39	56.4	46	3.55	31	0
1993	65.4	38	72.6	48	58.2	30	4.13	22	0
1992	64.7	46	72	53	57.3	38	3.22	34	0
1991	64.3	52	72.7	47	55.9	51	4.11	23	0
1990	66	32	74.8	29	57.2	39	2.48	41	0
1989	65	43	73.3	42	56.7	44	4.56	17	0
1988	64.2	56	72.6	48	55.8	52	3.59	29	0
1987	65.1	41	72.2	52	57.9	33	3.28	33	0
1986	63.7	59	71.6	59	55.7	54	0.82	60	0
1985	66.9	24	75.3	21	58.5	26	0.81	61	0
1984	62.6	61	70.9	62	54.3	61	5.06	12	0
1983	68.1	14	76.7	9	59.5	15	1.79	47	0
1982	65.7	35	73.8	38	57.7	36	1.12	58	0
1981	65.2	39	72.5	50	57.9	33	4.33	19	0
1980	69.6	5	78.5	3	60.7	9	1.28	57	0
1979	64.3	52	71.7	58	56.8	42	4.40	18	0
1978	62.5	62	71	61	54	62	5.56	10	0
1977	65.6	37	72	53	59.2	20	4.06	24	0
1976	64.2	56	73.6	39	54.7	60	1.49	53	0
1975	61.9	63	70	63	53.7	63	6.57	5	0
1974	64.2	56	71.9	56	56.6	45	5.95	8	0
1973	65.7	35	75.1	23	56.3	47	1.88	45	0
1972	66.8	27	75.3	21	58.3	28	3.09	35	0
1971	68.1	14	74.4	33	61.7	4	3.77	28	0
1970	67	22	75.1	23	58.8	23	1.79	47	0
1969	64.8	45	73.2	44	56.3	47	2.64	40	0
1968	65.9	33	76	13	55.7	54	1.70	49	0
1967	64.6	48	71.5	60	57.6	37	1.57	52	0
1966	63.6	60	72	53	55.3	58	7.50	2	0
1965	64.4	50	71.8	57	56.9	41	1.01	59	0
1964	64.3	52	72.8	46	55.8	52	3.07	36	0
1963									4

Warmest, coldest, wettest and driest

Warmest
Year	Mean, °F
2015	70.9
2005	70.2
2025	69.8
2018	69.8
2021	69.6
1980	69.6
2017	69
2011	69
2016	68.9
2023	68.6
More years share the last value

Coldest
Year	Mean, °F
1975	61.9
1978	62.5
1984	62.6
1966	63.6
1986	63.7
1988	64.2
1976	64.2
1974	64.2
2009	64.3
1991	64.3
More years share the last value

Wettest
Year	Precipitation, in
2026	8.76
1966	7.50
2008	7.46
2023	6.78
1975	6.57
1996	6.41
2004	6.37
1974	5.95
1999	5.65
1978	5.56

Driest
Year	Precipitation, in
2024	0.24
2019	0.61
1985	0.81
1986	0.82
1965	1.01
1982	1.12
1980	1.28
2007	1.31
2005	1.31
1997	1.42

The hottest, coldest and wettest days

Hottest day: 86°F; 10 September 2026
Coldest night: 52°F; 15 September 2026
Wettest day: 3.06 in; 13 September 2026

Every month, season and year

Months

Seasons

Years

Islip, NY the day's answers

All-time records

Every answer in words

September 2026 brought 8.76 in of precipitation in Islip, NY, the wettest September on record, in 63 years since 1964; provisional.
The hottest day of September 2026 in Islip, NY: 86°F on Thursday 10 September 2026.
The coldest night of September 2026 in Islip, NY: a low of 52°F on Tuesday 15 September 2026.
The wettest day of September 2026 in Islip, NY: 3.06 in on Sunday 13 September 2026.