Norristown Threshold Days by Year (USC00366370)
17 fixed thresholds counted per year at Norristown (USC00366370): hot days, frost, tropical nights and heavy rain, with the most days in a year.
Key Facts for Norristown Thresholds
- Norristown: days with 10 mm (0.39 in) or more of precipitation in 57 years, most in 2018 with 60.
- Norristown: days with 25 mm (0.98 in) or more of precipitation in 57 years, most in 2003 with 25.
- Norristown: days with a maximum temperature at or above 30 C (86 F) in 51 years, most in 2015 with 100.
- Norristown: days with a maximum temperature at or above 90 F (32.2 C) in 51 years, most in 2016 with 64.
- 17 fixed thresholds have at least one qualifying day at Norristown.
Days at or above 30 C (86 F)
51 years with a qualifying day| Year | Days | Decade average |
|---|---|---|
| 1952 | 54 | 57.3 |
| 1953 | 56 | 57.3 |
| 1954 | 53 | 57.3 |
| 1955 | 62 | 57.3 |
| 1956 | 48 | 57.3 |
| 1957 | 71 | 57.3 |
| 1958 | 43 | 57.3 |
| 1959 | 71 | 57.3 |
| 1960 | 34 | 53.7 |
| 1961 | 57 | 53.7 |
| 1962 | 59 | 53.7 |
| 1963 | 54 | 53.7 |
| 1964 | 63 | 53.7 |
| 1965 | 53 | 53.7 |
| 1966 | 62 | 53.7 |
| 1967 | 39 | 53.7 |
| 1968 | 57 | 53.7 |
| 1969 | 59 | 53.7 |
| 1970 | 73 | 51 |
| 1971 | 66 | 51 |
| 1972 | 49 | 51 |
| 1978 | 51 | 51 |
| 1979 | 16 | 51 |
| 1980 | 77 | 51.3 |
| 1981 | 42 | 51.3 |
| 1982 | 34 | 51.3 |
| 1983 | 78 | 51.3 |
| 1984 | 45 | 51.3 |
| 1985 | 43 | 51.3 |
| 1986 | 40 | 51.3 |
| 2001 | 71 | 67.9 |
| 2002 | 83 | 67.9 |
| 2003 | 68 | 67.9 |
| 2004 | 73 | 67.9 |
| 2005 | 96 | 67.9 |
| 2008 | 43 | 67.9 |
| 2009 | 41 | 67.9 |
| 2011 | 81 | 72.9 |
| 2012 | 77 | 72.9 |
| 2013 | 63 | 72.9 |
| 2014 | 74 | 72.9 |
| 2015 | 100 | 72.9 |
| 2016 | 96 | 72.9 |
| 2017 | 51 | 72.9 |
| 2018 | 54 | 72.9 |
| 2019 | 60 | 72.9 |
| 2020 | 55 | 60 |
| 2022 | 68 | 60 |
| 2023 | 55 | 60 |
| 2025 | 59 | 60 |
| 2026 | 63 | 60 |
| Year | First date | Last date |
|---|---|---|
| 1952 | 1952-05-28 | 1952-09-13 |
| 1953 | 1953-05-11 | 1953-09-29 |
| 1954 | 1954-05-31 | 1954-10-13 |
| 1955 | 1955-05-05 | 1955-09-20 |
| 1956 | 1956-04-28 | 1956-09-23 |
| 1957 | 1957-04-21 | 1957-09-22 |
| 1958 | 1958-06-11 | 1958-10-10 |
| 1959 | 1959-05-07 | 1959-10-07 |
| 1960 | 1960-04-14 | 1960-09-09 |
| 1961 | 1961-05-09 | 1961-09-25 |
| 1962 | 1962-04-26 | 1962-10-12 |
| 1963 | 1963-04-03 | 1963-10-07 |
| 1964 | 1964-05-08 | 1964-09-23 |
| 1965 | 1965-05-03 | 1965-09-23 |
| 1966 | 1966-05-06 | 1966-09-11 |
| 1967 | 1967-06-03 | 1967-10-05 |
| 1968 | 1968-06-06 | 1968-10-02 |
| 1969 | 1969-04-27 | 1969-09-17 |
| 1970 | 1970-05-09 | 1970-09-26 |
| 1971 | 1971-05-19 | 1971-09-16 |
| 1972 | 1972-04-19 | 1972-09-26 |
| 1978 | 1978-05-21 | 1978-09-19 |
| 1979 | 1979-05-10 | 1979-08-11 |
| 1980 | 1980-05-06 | 1980-09-23 |
| 1981 | 1981-05-23 | 1981-09-15 |
| 1982 | 1982-06-01 | 1982-09-15 |
| 1983 | 1983-04-29 | 1983-10-05 |
| 1984 | 1984-05-23 | 1984-09-25 |
| 1985 | 1985-04-20 | 1985-09-21 |
| 1986 | 1986-05-07 | 1986-10-01 |
| 2001 | 2001-04-10 | 2001-09-23 |
| 2002 | 2002-04-17 | 2002-10-06 |
| 2003 | 2003-04-17 | 2003-09-16 |
| 2004 | 2004-04-19 | 2004-09-24 |
| 2005 | 2005-04-20 | 2005-09-24 |
| 2008 | 2008-04-19 | 2008-09-16 |
| 2009 | 2009-04-26 | 2009-08-27 |
| 2011 | 2011-04-25 | 2011-09-26 |
| 2012 | 2012-04-17 | 2012-09-12 |
| 2013 | 2013-04-11 | 2013-10-06 |
| 2014 | 2014-05-11 | 2014-09-28 |
| 2015 | 2015-05-05 | 2015-09-25 |
| 2016 | 2016-04-27 | 2016-10-20 |
| 2017 | 2017-04-12 | 2017-09-28 |
| 2018 | 2018-05-03 | 2018-09-07 |
| 2019 | 2019-05-21 | 2019-10-03 |
| 2020 | 2020-06-05 | 2020-09-09 |
| 2022 | 2022-05-21 | 2022-09-20 |
| 2023 | 2023-04-14 | 2023-09-13 |
| 2025 | 2025-03-30 | 2025-09-29 |
| 2026 | 2026-04-15 | 2026-10-03 |
Every Fixed Threshold
| Threshold | Years with a qualifying day | Most days in a year | Year | Latest year days |
|---|---|---|---|---|
| 30 C (86 F): Days | 51 | 100 | 2015 | 63 |
| 35 C (95 F): Days | 45 | 30 | 2002 | 9 |
| 40 C (104 F): Days | 3 | 2 | 2005 | 2 |
| 90 F (32.2 C): Days | 51 | 64 | 2016 | 23 |
| 100 F (37.8 C): Days | 18 | 9 | 2002 | 3 |
| 0 C (32 F): Ice days (max | 51 | 34 | 1979 | 23 |
| 0 C (32 F): Frost days (min | 48 | 123 | 1981 | 77 |
| -10 C (14 F): Days with min | 47 | 32 | 2022 | 24 |
| -20 C (-4 F): Days with min | 5 | 3 | 1982 | 2 |
| 20 C (68 F): Tropical nights (min | 48 | 65 | 2012 | 47 |
| 25 C (77 F): Days with min | 15 | 5 | 2025 | 2 |
| 10 mm (0.39 in): Days with 10 mm or more rain | 57 | 60 | 2018 | 25 |
| 25 mm (0.98 in): Days with 25 mm or more rain | 57 | 25 | 2003 | 13 |
| 50 mm (1.97 in): Days with 50 mm or more rain | 49 | 6 | 1952 | 3 |
| 100 mm (3.94 in): Days with 100 mm or more rain | 9 | 2 | 1955 | 1 |
| 10 cm (3.9 in): Days with 10 cm or more snowfall | 30 | 5 | 2014 | 1 |
| 25 cm (9.8 in): Days with 25 cm or more snowfall | 11 | 1 | 1956 | 1 |
Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1952.
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 (2026-10-17).