Rochester Threshold Days by Year

16 fixed thresholds counted per year at Rochester (USC00436893): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Rochester Thresholds

Rochester: days with 10 mm (0.39 in) or more of precipitation in 85 years, most in 1945 with 51.
Rochester: days with 25 mm (0.98 in) or more of precipitation in 85 years, most in 1976 with 18.
Rochester: days with 10 cm (3.9 in) or more of snowfall in 70 years, most in 1972 with 14.
Rochester: days with 50 mm (1.97 in) or more of precipitation in 60 years, most in 1945 with 4.
16 fixed thresholds have at least one qualifying day at Rochester.

Days at or above 30 C (86 F)

47 years with a qualifying day

Days per year at Rochester with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 30 in 1999.

Days at or above 30 C (86 F) per year at Rochester
Year	Days	Decade average
1966	15	12
1967	7	12
1968	13	12
1969	13	12
1970	22	16.6
1971	13	16.6
1972	8	16.6
1973	21	16.6
1974	10	16.6
1975	22	16.6
1976	14	16.6
1977	16	16.6
1978	23	16.6
1979	17	16.6
1980	11	10.6
1981	6	10.6
1982	9	10.6
1983	21	10.6
1984	10	10.6
1985	4	10.6
1986	3	10.6
1987	17	10.6
1988	24	10.6
1989	1	10.6
1990	13	12.2
1991	18	12.2
1992	5	12.2
1993	11	12.2
1994	9	12.2
1996	4	12.2
1997	9	12.2
1998	11	12.2
1999	30	12.2
2000	5	12.3
2001	23	12.3
2002	27	12.3
2003	10	12.3
2004	6	12.3
2006	10	12.3
2008	8	12.3
2009	9	12.3
2010	19	13.8
2011	12	13.8
2012	16	13.8
2013	9	13.8
2016	14	13.8
2017	13	13.8

For each year, a bar from the first to the last day at Rochester meeting 30 C (86 F).

First to last qualifying date each year at Rochester
Year	First date	Last date
1966	1966-06-07	1966-08-12
1967	1967-06-04	1967-07-22
1968	1968-06-07	1968-09-21
1969	1969-06-03	1969-09-02
1970	1970-05-02	1970-09-23
1971	1971-05-20	1971-09-06
1972	1972-05-24	1972-08-26
1973	1973-06-06	1973-09-06
1974	1974-05-16	1974-08-23
1975	1975-05-21	1975-08-06
1976	1976-04-18	1976-08-23
1977	1977-05-18	1977-08-30
1978	1978-05-27	1978-08-20
1979	1979-05-10	1979-08-06
1980	1980-05-24	1980-08-27
1981	1981-06-17	1981-08-12
1982	1982-07-08	1982-09-14
1983	1983-06-13	1983-09-21
1984	1984-06-09	1984-08-15
1985	1985-07-26	1985-08-16
1986	1986-05-19	1986-07-08
1987	1987-05-30	1987-08-18
1988	1988-06-13	1988-08-13
1989	1989-07-28	1989-07-28
1990	1990-04-28	1990-08-06
1991	1991-05-25	1991-08-31
1992	1992-05-22	1992-08-27
1993	1993-07-06	1993-09-01
1994	1994-05-23	1994-07-22
1996	1996-05-21	1996-08-08
1997	1997-06-11	1997-08-17
1998	1998-05-30	1998-08-27
1999	1999-05-23	1999-09-05
2000	2000-05-07	2000-09-01
2001	2001-05-02	2001-09-09
2002	2002-04-16	2002-09-10
2003	2003-06-24	2003-08-16
2004	2004-06-09	2004-08-30
2006	2006-06-01	2006-08-03
2008	2008-06-08	2008-09-06
2009	2009-04-26	2009-08-19
2010	2010-05-26	2010-09-03
2011	2011-06-01	2011-08-02
2012	2012-04-17	2012-08-10
2013	2013-06-02	2013-09-12
2016	2016-05-28	2016-08-13
2017	2017-05-18	2017-09-28

Every Fixed Threshold

Fixed thresholds at Rochester
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	47	30	1999	13
35 C (95 F): Days	7	2	1975	1
90 F (32.2 C): Days	35	13	2002	6
0 C (32 F): Ice days (max	47	91	1989	53
0 C (32 F): Frost days (min	45	214	1972	159
-10 C (14 F): Days with min	45	101	1970	63
-20 C (-4 F): Days with min	45	41	1968	9
-30 C (-22 F): Days with min	23	11	1971	2
20 C (68 F): Tropical nights (min	17	3	1999	2
10 mm (0.39 in): Days with 10 mm or more rain	85	51	1945	44
25 mm (0.98 in): Days with 25 mm or more rain	85	18	1976	14
50 mm (1.97 in): Days with 50 mm or more rain	60	4	1945	2
100 mm (3.94 in): Days with 100 mm or more rain	2	1	1999	1
10 cm (3.9 in): Days with 10 cm or more snowfall	70	14	1972	8
25 cm (9.8 in): Days with 25 cm or more snowfall	43	5	1969	4
50 cm (19.7 in): Days with 50 cm or more snowfall	7	1	1969	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1966.

Download the Data

Data for Rochester threshold days by year: CSV or JSON. Field meanings are on the data page.

Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-14 (14 October 2026). Threshold counts are computed by this site.

Data as of 2025-12-31. Last revised 31 December 2025 (2025-12-31).

Rochester Threshold Days by Year

Key Facts for Rochester Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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