Tiber Dam Threshold Days by Year (USC00248233)
17 fixed thresholds counted per year at Tiber Dam (USC00248233): hot days, frost, tropical nights and heavy rain, with the most days in a year.
Key Facts for Tiber Dam Thresholds
- Tiber Dam: days with 10 mm (0.39 in) or more of precipitation in 56 years, most in 1975 with 16.
- Tiber Dam: nights with a minimum temperature at or below 0 C (32 F) in 46 years, most in 1955 with 203.
- Tiber Dam: nights with a minimum temperature at or below -10 C (14 F) in 46 years, most in 1955 with 110.
- Tiber Dam: nights with a minimum temperature at or below -20 C (-4 F) in 46 years, most in 1978 with 45.
- 17 fixed thresholds have at least one qualifying day at Tiber Dam.
Days at or above 30 C (86 F)
45 years with a qualifying day| Year | Days | Decade average |
|---|---|---|
| 1953 | 47 | 44 |
| 1954 | 40 | 44 |
| 1955 | 43 | 44 |
| 1956 | 44 | 44 |
| 1957 | 43 | 44 |
| 1958 | 48 | 44 |
| 1959 | 43 | 44 |
| 1960 | 51 | 49.3 |
| 1961 | 72 | 49.3 |
| 1962 | 42 | 49.3 |
| 1963 | 61 | 49.3 |
| 1964 | 38 | 49.3 |
| 1965 | 25 | 49.3 |
| 1966 | 48 | 49.3 |
| 1967 | 65 | 49.3 |
| 1968 | 35 | 49.3 |
| 1969 | 56 | 49.3 |
| 1970 | 52 | 43 |
| 1971 | 57 | 43 |
| 1972 | 42 | 43 |
| 1973 | 60 | 43 |
| 1974 | 45 | 43 |
| 1975 | 27 | 43 |
| 1976 | 36 | 43 |
| 1977 | 31 | 43 |
| 1978 | 29 | 43 |
| 1979 | 51 | 43 |
| 1980 | 32 | 45.1 |
| 1981 | 55 | 45.1 |
| 1982 | 40 | 45.1 |
| 1983 | 45 | 45.1 |
| 1984 | 56 | 45.1 |
| 1986 | 42 | 45.1 |
| 1987 | 46 | 45.1 |
| 1990 | 63 | 63 |
| 2006 | 49 | 42 |
| 2008 | 37 | 42 |
| 2009 | 40 | 42 |
| 2010 | 25 | 42.8 |
| 2011 | 52 | 42.8 |
| 2012 | 48 | 42.8 |
| 2013 | 46 | 42.8 |
| 2024 | 44 | 40 |
| 2025 | 39 | 40 |
| 2026 | 37 | 40 |
| Year | First date | Last date |
|---|---|---|
| 1953 | 1953-05-06 | 1953-10-10 |
| 1954 | 1954-05-18 | 1954-09-03 |
| 1955 | 1955-06-22 | 1955-09-07 |
| 1956 | 1956-05-19 | 1956-09-26 |
| 1957 | 1957-05-02 | 1957-09-28 |
| 1958 | 1958-05-11 | 1958-09-12 |
| 1959 | 1959-06-12 | 1959-09-14 |
| 1960 | 1960-05-11 | 1960-10-06 |
| 1961 | 1961-05-26 | 1961-09-16 |
| 1962 | 1962-06-19 | 1962-09-27 |
| 1963 | 1963-05-29 | 1963-10-03 |
| 1964 | 1964-05-19 | 1964-10-13 |
| 1965 | 1965-06-10 | 1965-08-12 |
| 1966 | 1966-05-04 | 1966-09-23 |
| 1967 | 1967-06-29 | 1967-09-30 |
| 1968 | 1968-04-30 | 1968-09-12 |
| 1969 | 1969-05-24 | 1969-09-18 |
| 1970 | 1970-06-02 | 1970-09-30 |
| 1971 | 1971-05-27 | 1971-10-09 |
| 1972 | 1972-05-30 | 1972-08-30 |
| 1973 | 1973-05-15 | 1973-09-29 |
| 1974 | 1974-06-11 | 1974-09-26 |
| 1975 | 1975-07-04 | 1975-09-25 |
| 1976 | 1976-05-13 | 1976-09-21 |
| 1977 | 1977-06-01 | 1977-08-19 |
| 1978 | 1978-06-05 | 1978-09-05 |
| 1979 | 1979-06-12 | 1979-10-10 |
| 1980 | 1980-04-20 | 1980-10-07 |
| 1981 | 1981-06-26 | 1981-09-19 |
| 1982 | 1982-05-24 | 1982-09-10 |
| 1983 | 1983-05-25 | 1983-09-01 |
| 1984 | 1984-05-29 | 1984-10-09 |
| 1986 | 1986-05-20 | 1986-08-29 |
| 1987 | 1987-04-27 | 1987-09-24 |
| 1990 | 1990-06-23 | 1990-09-25 |
| 2006 | 2006-05-20 | 2006-09-06 |
| 2008 | 2008-05-16 | 2008-08-26 |
| 2009 | 2009-05-29 | 2009-09-25 |
| 2010 | 2010-06-28 | 2010-08-27 |
| 2011 | 2011-06-28 | 2011-09-30 |
| 2012 | 2012-04-23 | 2012-09-18 |
| 2013 | 2013-05-12 | 2013-09-17 |
| 2024 | 2024-06-23 | 2024-09-25 |
| 2025 | 2025-05-11 | 2025-09-26 |
| 2026 | 2026-05-14 | 2026-09-13 |
Every Fixed Threshold
| Threshold | Years with a qualifying day | Most days in a year | Year | Latest year days |
|---|---|---|---|---|
| 30 C (86 F): Days | 45 | 72 | 1961 | 37 |
| 35 C (95 F): Days | 45 | 27 | 1971 | 10 |
| 40 C (104 F): Days | 6 | 2 | 1960 | 2 |
| 90 F (32.2 C): Days | 45 | 47 | 1961 | 24 |
| 100 F (37.8 C): Days | 17 | 7 | 1971 | 2 |
| 0 C (32 F): Ice days (max | 45 | 89 | 1978 | 16 |
| 0 C (32 F): Frost days (min | 46 | 203 | 1955 | 107 |
| -10 C (14 F): Days with min | 46 | 110 | 1955 | 25 |
| -20 C (-4 F): Days with min | 46 | 45 | 1978 | 10 |
| -30 C (-22 F): Days with min | 38 | 13 | 1982 | 4 |
| -40 C (-40 F): Days with min | 8 | 2 | 1969 | 1 |
| 20 C (68 F): Tropical nights (min | 8 | 2 | 1961 | 1 |
| 10 mm (0.39 in): Days with 10 mm or more rain | 56 | 16 | 1975 | 3 |
| 25 mm (0.98 in): Days with 25 mm or more rain | 35 | 5 | 1970 | 1 |
| 50 mm (1.97 in): Days with 50 mm or more rain | 5 | 1 | 1959 | 1 |
| 100 mm (3.94 in): Days with 100 mm or more rain | 1 | 0 | n/a | 1 |
| 10 cm (3.9 in): Days with 10 cm or more snowfall | 10 | 3 | 1965 | 4 |
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
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 (2026-10-14).