Janesville Threshold Days by Year (USC00473979)

17 fixed thresholds counted per year at Janesville (USC00473979): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Janesville Thresholds

Janesville: days with a maximum temperature at or above 30 C (86 F) in 42 years, most in 1955 with 67.
Janesville: days with a maximum temperature at or above 90 F (32.2 C) in 42 years, most in 1955 with 43.
Janesville: days with a maximum temperature at or below 0 C (32 F) in 42 years, most in 1978 with 76.
Janesville: nights with a minimum temperature at or below 0 C (32 F) in 42 years, most in 1893 with 171.
17 fixed thresholds have at least one qualifying day at Janesville.

Days at or above 30 C (86 F)

42 years with a qualifying day

Days per year at Janesville with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 67 in 1955.

Days at or above 30 C (86 F) per year at Janesville
Year	Days	Decade average
1893	32	45.5
1894	59	45.5
1945	35	47.6
1946	47	47.6
1947	53	47.6
1948	51	47.6
1949	52	47.6
1950	16	41.9
1951	16	41.9
1952	53	41.9
1953	58	41.9
1954	48	41.9
1955	67	41.9
1956	43	41.9
1957	40	41.9
1958	31	41.9
1959	47	41.9
1960	32	39.3
1961	38	39.3
1962	42	39.3
1963	54	39.3
1964	48	39.3
1965	34	39.3
1966	48	39.3
1967	19	39.3
1968	36	39.3
1969	42	39.3
1970	58	47.7
1971	57	47.7
1972	39	47.7
1973	42	47.7
1974	33	47.7
1975	46	47.7
1976	60	47.7
1977	49	47.7
1978	51	47.7
1979	42	47.7
1980	46	34.4
1982	16	34.4
1984	34	34.4
1985	42	34.4
1986	34	34.4

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

First to last qualifying date each year at Janesville
Year	First date	Last date
1893	1893-04-07	1893-09-21
1894	1894-05-14	1894-09-08
1945	1945-06-23	1945-09-08
1946	1946-06-10	1946-09-18
1947	1947-06-09	1947-09-20
1948	1948-06-01	1948-09-19
1949	1949-05-03	1949-08-27
1950	1950-05-24	1950-08-16
1951	1951-05-16	1951-09-12
1952	1952-04-28	1952-09-28
1953	1953-05-29	1953-10-20
1954	1954-06-09	1954-10-03
1955	1955-05-03	1955-09-19
1956	1956-05-22	1956-09-22
1957	1957-04-30	1957-09-01
1958	1958-05-14	1958-08-31
1959	1959-05-02	1959-09-22
1960	1960-06-27	1960-09-08
1961	1961-05-13	1961-09-10
1962	1962-05-14	1962-09-13
1963	1963-05-08	1963-10-06
1964	1964-05-18	1964-09-09
1965	1965-05-02	1965-09-09
1966	1966-06-04	1966-09-11
1967	1967-05-18	1967-08-16
1968	1968-06-04	1968-09-03
1969	1969-05-16	1969-10-01
1970	1970-04-29	1970-09-20
1971	1971-05-17	1971-10-02
1972	1972-05-17	1972-08-30
1973	1973-06-08	1973-09-03
1974	1974-05-21	1974-08-27
1975	1975-05-18	1975-10-13
1976	1976-06-06	1976-10-01
1977	1977-04-17	1977-09-04
1978	1978-05-25	1978-09-20
1979	1979-05-08	1979-09-11
1980	1980-04-22	1980-09-13
1982	1982-05-14	1982-09-30
1984	1984-06-05	1984-09-25
1985	1985-04-18	1985-09-19
1986	1986-05-31	1986-09-25

Every Fixed Threshold

Fixed thresholds at Janesville
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	42	67	1955	34
35 C (95 F): Days	33	17	1955	3
90 F (32.2 C): Days	42	43	1955	15
100 F (37.8 C): Days	10	4	1953	1
0 C (32 F): Ice days (max	42	76	1978	40
0 C (32 F): Frost days (min	42	171	1893	135
-10 C (14 F): Days with min	42	80	1893	67
-20 C (-4 F): Days with min	42	30	1963	19
-30 C (-22 F): Days with min	9	2	1951	1
20 C (68 F): Tropical nights (min	42	29	1959	10
25 C (77 F): Days with min	4	1	1894	1
10 mm (0.39 in): Days with 10 mm or more rain	42	36	1945	27
25 mm (0.98 in): Days with 25 mm or more rain	42	14	1972	6
50 mm (1.97 in): Days with 50 mm or more rain	24	6	1978	1
100 mm (3.94 in): Days with 100 mm or more rain	2	1	1952	1
10 cm (3.9 in): Days with 10 cm or more snowfall	37	5	1950	3
25 cm (9.8 in): Days with 25 cm or more snowfall	3	1	1959	1

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1893.

Download the Data

Data for Janesville 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).

Janesville Threshold Days by Year (USC00473979)

Key Facts for Janesville Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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