Mercer Threshold Days by Year (USC00365651)

16 fixed thresholds counted per year at Mercer (USC00365651): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Mercer Thresholds

Mercer: days with 10 mm (0.39 in) or more of precipitation in 51 years, most in 1956 with 47.
Mercer: days with 25 mm (0.98 in) or more of precipitation in 51 years, most in 2003 with 13.
Mercer: days with a maximum temperature at or above 30 C (86 F) in 49 years, most in 1991 with 47.
Mercer: days with a maximum temperature at or below 0 C (32 F) in 49 years, most in 1960 with 61.
16 fixed thresholds have at least one qualifying day at Mercer.

Days at or above 30 C (86 F)

49 years with a qualifying day

Days per year at Mercer with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 47 in 1991.

Days at or above 30 C (86 F) per year at Mercer
Year	Days	Decade average
1953	45	25.6
1956	12	25.6
1957	20	25.6
1958	8	25.6
1959	43	25.6
1960	12	20.8
1961	29	20.8
1962	31	20.8
1963	21	20.8
1966	28	20.8
1967	11	20.8
1968	16	20.8
1969	18	20.8
1970	22	16.6
1971	18	16.6
1972	11	16.6
1973	24	16.6
1974	11	16.6
1975	22	16.6
1976	11	16.6
1977	19	16.6
1978	16	16.6
1979	12	16.6
1980	17	20.6
1981	10	20.6
1982	13	20.6
1983	38	20.6
1984	19	20.6
1985	10	20.6
1986	16	20.6
1987	26	20.6
1988	42	20.6
1989	15	20.6
1990	13	22.2
1991	47	22.2
1992	9	22.2
1994	18	22.2
1995	40	22.2
1996	5	22.2
1997	19	22.2
1998	19	22.2
1999	30	22.2
2000	6	16.3
2001	15	16.3
2002	28	16.3
2003	3	16.3
2004	4	16.3
2006	20	16.3
2007	38	16.3

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

First to last qualifying date each year at Mercer
Year	First date	Last date
1953	1953-05-10	1953-09-30
1956	1956-06-12	1956-09-02
1957	1957-06-13	1957-09-03
1958	1958-06-05	1958-08-07
1959	1959-05-06	1959-09-29
1960	1960-06-28	1960-09-08
1961	1961-06-12	1961-09-25
1962	1962-05-14	1962-09-13
1963	1963-05-09	1963-07-29
1966	1966-06-23	1966-09-03
1967	1967-06-11	1967-07-10
1968	1968-06-08	1968-08-24
1969	1969-05-29	1969-09-01
1970	1970-05-22	1970-09-24
1971	1971-06-05	1971-09-10
1972	1972-07-11	1972-08-24
1973	1973-06-10	1973-09-05
1974	1974-06-09	1974-09-11
1975	1975-06-22	1975-08-26
1976	1976-04-18	1976-09-09
1977	1977-05-17	1977-09-01
1978	1978-05-27	1978-09-21
1979	1979-05-09	1979-09-04
1980	1980-06-26	1980-09-13
1981	1981-06-14	1981-07-18
1982	1982-07-07	1982-09-13
1983	1983-06-13	1983-09-10
1984	1984-06-07	1984-09-22
1985	1985-04-23	1985-09-08
1986	1986-04-28	1986-09-30
1987	1987-05-28	1987-08-17
1988	1988-05-30	1988-08-17
1989	1989-06-25	1989-09-09
1990	1990-04-25	1990-09-01
1991	1991-05-13	1991-09-16
1992	1992-06-14	1992-08-26
1994	1994-06-09	1994-07-21
1995	1995-06-17	1995-09-08
1996	1996-06-30	1996-09-09
1997	1997-06-20	1997-09-30
1998	1998-05-19	1998-09-27
1999	1999-06-06	1999-09-12
2000	2000-06-10	2000-09-03
2001	2001-06-14	2001-09-07
2002	2002-06-24	2002-09-10
2003	2003-06-25	2003-08-21
2004	2004-06-09	2004-08-03
2006	2006-05-30	2006-08-27
2007	2007-05-25	2007-10-09

Every Fixed Threshold

Fixed thresholds at Mercer
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	49	47	1991	38
35 C (95 F): Days	6	12	1953	1
90 F (32.2 C): Days	40	29	1988	13
100 F (37.8 C): Days	1	2	1953	2
0 C (32 F): Ice days (max	49	61	1960	50
0 C (32 F): Frost days (min	46	174	1958	129
-10 C (14 F): Days with min	46	61	2004	34
-20 C (-4 F): Days with min	39	17	1963	3
-30 C (-22 F): Days with min	3	3	1963	1
20 C (68 F): Tropical nights (min	37	14	1977	5
10 mm (0.39 in): Days with 10 mm or more rain	51	47	1956	37
25 mm (0.98 in): Days with 25 mm or more rain	51	13	2003	9
50 mm (1.97 in): Days with 50 mm or more rain	31	4	1987	2
100 mm (3.94 in): Days with 100 mm or more rain	2	1	2002	1
10 cm (3.9 in): Days with 10 cm or more snowfall	38	5	1971	5
25 cm (9.8 in): Days with 25 cm or more snowfall	3	1	1966	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1953.

Download the Data

Data for Mercer 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 2026-10-17 (17 October 2026). Threshold counts are computed by this site.

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

Mercer Threshold Days by Year (USC00365651)

Key Facts for Mercer Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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