Isit Threshold Days by Year (RSM00024951)
13 fixed thresholds counted per year at Isit (RSM00024951): hot days, frost, tropical nights and heavy rain, with the most days in a year.
Key Facts for Isit Thresholds
- Isit: days with 10 mm (0.39 in) or more of precipitation in 84 years, most in 1983 with 15.
- Isit: nights with a minimum temperature at or below 0 C (32 F) in 81 years, most in 1964 with 255.
- Isit: nights with a minimum temperature at or below -10 C (14 F) in 81 years, most in 1987 with 196.
- Isit: nights with a minimum temperature at or below -20 C (-4 F) in 81 years, most in 1960 with 166.
- 13 fixed thresholds have at least one qualifying day at Isit.
Days at or above 30 C (86 F)
76 years with a qualifying day| Year | Days | Decade average |
|---|---|---|
| 1936 | 3 | 5 |
| 1937 | 9 | 5 |
| 1938 | 3 | 5 |
| 1939 | 5 | 5 |
| 1940 | 3 | 12 |
| 1941 | 23 | 12 |
| 1942 | 12 | 12 |
| 1948 | 12 | 12 |
| 1949 | 10 | 12 |
| 1950 | 6 | 6.6 |
| 1951 | 4 | 6.6 |
| 1952 | 12 | 6.6 |
| 1953 | 6 | 6.6 |
| 1954 | 20 | 6.6 |
| 1955 | 3 | 6.6 |
| 1956 | 8 | 6.6 |
| 1957 | 3 | 6.6 |
| 1958 | 3 | 6.6 |
| 1959 | 1 | 6.6 |
| 1960 | 4 | 4.8 |
| 1961 | 8 | 4.8 |
| 1962 | 6 | 4.8 |
| 1963 | 3 | 4.8 |
| 1964 | 5 | 4.8 |
| 1965 | 1 | 4.8 |
| 1966 | 3 | 4.8 |
| 1967 | 1 | 4.8 |
| 1968 | 12 | 4.8 |
| 1969 | 5 | 4.8 |
| 1970 | 17 | 5.1 |
| 1971 | 6 | 5.1 |
| 1973 | 9 | 5.1 |
| 1974 | 2 | 5.1 |
| 1975 | 2 | 5.1 |
| 1976 | 1 | 5.1 |
| 1977 | 4 | 5.1 |
| 1978 | 3 | 5.1 |
| 1979 | 2 | 5.1 |
| 1980 | 6 | 4.9 |
| 1981 | 6 | 4.9 |
| 1982 | 1 | 4.9 |
| 1983 | 1 | 4.9 |
| 1985 | 3 | 4.9 |
| 1986 | 16 | 4.9 |
| 1987 | 1 | 4.9 |
| 1988 | 8 | 4.9 |
| 1989 | 2 | 4.9 |
| 1990 | 13 | 7.9 |
| 1991 | 6 | 7.9 |
| 1992 | 8 | 7.9 |
| 1993 | 6 | 7.9 |
| 1994 | 1 | 7.9 |
| 1995 | 9 | 7.9 |
| 1996 | 10 | 7.9 |
| 1997 | 5 | 7.9 |
| 1998 | 11 | 7.9 |
| 1999 | 10 | 7.9 |
| 2000 | 4 | 5 |
| 2001 | 13 | 5 |
| 2002 | 5 | 5 |
| 2003 | 9 | 5 |
| 2004 | 1 | 5 |
| 2005 | 1 | 5 |
| 2006 | 2 | 5 |
| 2007 | 3 | 5 |
| 2008 | 9 | 5 |
| 2009 | 3 | 5 |
| 2010 | 8 | 8.1 |
| 2011 | 16 | 8.1 |
| 2012 | 7 | 8.1 |
| 2013 | 3 | 8.1 |
| 2014 | 6 | 8.1 |
| 2015 | 8 | 8.1 |
| 2016 | 2 | 8.1 |
| 2017 | 15 | 8.1 |
| 2018 | 8 | 8.1 |
| Year | First date | Last date |
|---|---|---|
| 1936 | 1936-07-21 | 1936-08-07 |
| 1937 | 1937-06-30 | 1937-08-04 |
| 1938 | 1938-06-27 | 1938-07-13 |
| 1939 | 1939-07-05 | 1939-08-15 |
| 1940 | 1940-06-30 | 1940-07-11 |
| 1941 | 1941-06-10 | 1941-08-24 |
| 1942 | 1942-07-03 | 1942-07-17 |
| 1948 | 1948-07-01 | 1948-08-19 |
| 1949 | 1949-06-06 | 1949-08-11 |
| 1950 | 1950-06-01 | 1950-07-05 |
| 1951 | 1951-07-03 | 1951-07-21 |
| 1952 | 1952-07-04 | 1952-08-06 |
| 1953 | 1953-06-21 | 1953-08-03 |
| 1954 | 1954-06-18 | 1954-08-06 |
| 1955 | 1955-08-02 | 1955-09-04 |
| 1956 | 1956-06-18 | 1956-08-03 |
| 1957 | 1957-07-05 | 1957-08-04 |
| 1958 | 1958-08-05 | 1958-08-13 |
| 1959 | 1959-07-06 | 1959-07-06 |
| 1960 | 1960-07-08 | 1960-07-13 |
| 1961 | 1961-07-27 | 1961-08-17 |
| 1962 | 1962-06-21 | 1962-08-04 |
| 1963 | 1963-07-22 | 1963-07-24 |
| 1964 | 1964-07-01 | 1964-07-26 |
| 1965 | 1965-07-07 | 1965-07-07 |
| 1966 | 1966-06-27 | 1966-06-29 |
| 1967 | 1967-07-03 | 1967-07-03 |
| 1968 | 1968-06-20 | 1968-07-29 |
| 1969 | 1969-07-30 | 1969-08-05 |
| 1970 | 1970-06-28 | 1970-07-23 |
| 1971 | 1971-06-05 | 1971-07-23 |
| 1973 | 1973-06-04 | 1973-08-06 |
| 1974 | 1974-07-15 | 1974-07-16 |
| 1975 | 1975-07-04 | 1975-08-07 |
| 1976 | 1976-07-17 | 1976-07-17 |
| 1977 | 1977-06-13 | 1977-07-13 |
| 1978 | 1978-08-09 | 1978-08-19 |
| 1979 | 1979-07-03 | 1979-07-04 |
| 1980 | 1980-07-12 | 1980-08-01 |
| 1981 | 1981-06-10 | 1981-07-19 |
| 1982 | 1982-07-28 | 1982-07-28 |
| 1983 | 1983-07-06 | 1983-07-06 |
| 1985 | 1985-07-01 | 1985-07-07 |
| 1986 | 1986-06-02 | 1986-08-09 |
| 1987 | 1987-08-14 | 1987-08-14 |
| 1988 | 1988-07-01 | 1988-07-27 |
| 1989 | 1989-07-07 | 1989-07-18 |
| 1990 | 1990-06-06 | 1990-08-13 |
| 1991 | 1991-07-04 | 1991-08-20 |
| 1992 | 1992-06-17 | 1992-07-12 |
| 1993 | 1993-06-19 | 1993-07-27 |
| 1994 | 1994-07-23 | 1994-07-23 |
| 1995 | 1995-06-10 | 1995-07-02 |
| 1996 | 1996-06-18 | 1996-07-22 |
| 1997 | 1997-07-16 | 1997-08-16 |
| 1998 | 1998-06-13 | 1998-08-20 |
| 1999 | 1999-06-19 | 1999-07-22 |
| 2000 | 2000-07-17 | 2000-07-21 |
| 2001 | 2001-07-04 | 2001-08-16 |
| 2002 | 2002-06-30 | 2002-08-09 |
| 2003 | 2003-06-16 | 2003-07-28 |
| 2004 | 2004-07-08 | 2004-07-08 |
| 2005 | 2005-07-28 | 2005-07-28 |
| 2006 | 2006-07-30 | 2006-08-02 |
| 2007 | 2007-06-29 | 2007-07-01 |
| 2008 | 2008-06-19 | 2008-07-27 |
| 2009 | 2009-06-30 | 2009-07-27 |
| 2010 | 2010-07-05 | 2010-07-29 |
| 2011 | 2011-06-12 | 2011-08-08 |
| 2012 | 2012-06-16 | 2012-08-03 |
| 2013 | 2013-06-22 | 2013-06-28 |
| 2014 | 2014-06-20 | 2014-07-17 |
| 2015 | 2015-07-09 | 2015-08-23 |
| 2016 | 2016-07-08 | 2016-07-09 |
| 2017 | 2017-06-12 | 2017-08-15 |
| 2018 | 2018-06-06 | 2018-07-09 |
Every Fixed Threshold
| Threshold | Years with a qualifying day | Most days in a year | Year | Latest year days |
|---|---|---|---|---|
| 30 C (86 F): Days | 76 | 23 | 1941 | 8 |
| 35 C (95 F): Days | 7 | 5 | 2011 | 2 |
| 90 F (32.2 C): Days | 49 | 12 | 1954 | 3 |
| 0 C (32 F): Ice days (max | 79 | 195 | 1956 | 79 |
| 0 C (32 F): Frost days (min | 81 | 255 | 1964 | 85 |
| -10 C (14 F): Days with min | 81 | 196 | 1987 | 62 |
| -20 C (-4 F): Days with min | 81 | 166 | 1960 | 55 |
| -30 C (-22 F): Days with min | 81 | 123 | 1941 | 39 |
| -40 C (-40 F): Days with min | 81 | 68 | 1965 | 9 |
| 20 C (68 F): Tropical nights (min | 21 | 3 | 1937 | 1 |
| 10 mm (0.39 in): Days with 10 mm or more rain | 84 | 15 | 1983 | 7 |
| 25 mm (0.98 in): Days with 25 mm or more rain | 40 | 6 | 2013 | 1 |
| 50 mm (1.97 in): Days with 50 mm or more rain | 6 | 1 | 1938 | 1 |
Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1936.
Download the Data
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 . Last revised (2025-12-31).