Alexandria Potomac Yar Threshold Days by Year (USC00440097)
17 fixed thresholds counted per year at Alexandria Potomac Yar (USC00440097): hot days, frost, tropical nights and heavy rain, with the most days in a year.
Key Facts for Alexandria Potomac Yar Thresholds
- Alexandria Potomac Yar: nights with a minimum temperature at or below 0 C (32 F) in 17 years, most in 1901 with 97.
- Alexandria Potomac Yar: nights with a minimum temperature at or above 20 C (68 F) in 17 years, most in 1959 with 74.
- Alexandria Potomac Yar: days with 10 mm (0.39 in) or more of precipitation in 17 years, most in 1899 with 40.
- Alexandria Potomac Yar: days with 25 mm (0.98 in) or more of precipitation in 17 years, most in 1952 with 15.
- 17 fixed thresholds have at least one qualifying day at Alexandria Potomac Yar.
Days at or above 30 C (86 F)
16 years with a qualifying day| Year | Days | Decade average |
|---|---|---|
| 1894 | 70 | 66.3 |
| 1897 | 55 | 66.3 |
| 1898 | 70 | 66.3 |
| 1899 | 70 | 66.3 |
| 1900 | 91 | 69 |
| 1901 | 69 | 69 |
| 1902 | 47 | 69 |
| 1949 | 87 | 87 |
| 1950 | 60 | 80.8 |
| 1951 | 80 | 80.8 |
| 1952 | 75 | 80.8 |
| 1953 | 75 | 80.8 |
| 1954 | 92 | 80.8 |
| 1956 | 74 | 80.8 |
| 1957 | 104 | 80.8 |
| 1959 | 86 | 80.8 |
| Year | First date | Last date |
|---|---|---|
| 1894 | 1894-05-04 | 1894-09-18 |
| 1897 | 1897-04-24 | 1897-10-16 |
| 1898 | 1898-05-02 | 1898-10-04 |
| 1899 | 1899-05-01 | 1899-09-08 |
| 1900 | 1900-05-08 | 1900-10-06 |
| 1901 | 1901-04-30 | 1901-09-16 |
| 1902 | 1902-04-22 | 1902-09-08 |
| 1949 | 1949-04-15 | 1949-10-11 |
| 1950 | 1950-05-06 | 1950-11-01 |
| 1951 | 1951-04-29 | 1951-10-06 |
| 1952 | 1952-04-20 | 1952-09-15 |
| 1953 | 1953-04-25 | 1953-09-30 |
| 1954 | 1954-04-19 | 1954-10-14 |
| 1956 | 1956-04-28 | 1956-09-24 |
| 1957 | 1957-04-21 | 1957-09-23 |
| 1959 | 1959-04-09 | 1959-10-06 |
Every Fixed Threshold
| Threshold | Years with a qualifying day | Most days in a year | Year | Latest year days |
|---|---|---|---|---|
| 30 C (86 F): Days | 16 | 104 | 1957 | 86 |
| 35 C (95 F): Days | 16 | 32 | 1900 | 8 |
| 40 C (104 F): Days | 3 | 2 | 1954 | 2 |
| 90 F (32.2 C): Days | 16 | 69 | 1900 | 37 |
| 100 F (37.8 C): Days | 8 | 7 | 1900 | 2 |
| 0 C (32 F): Ice days (max | 15 | 21 | 1899 | 8 |
| 0 C (32 F): Frost days (min | 17 | 97 | 1901 | 88 |
| -10 C (14 F): Days with min | 15 | 20 | 1899 | 7 |
| -20 C (-4 F): Days with min | 1 | 4 | 1899 | 4 |
| 20 C (68 F): Tropical nights (min | 17 | 74 | 1959 | 74 |
| 25 C (77 F): Days with min | 12 | 9 | 1900 | 4 |
| 10 mm (0.39 in): Days with 10 mm or more rain | 17 | 40 | 1899 | 31 |
| 25 mm (0.98 in): Days with 25 mm or more rain | 17 | 15 | 1952 | 12 |
| 50 mm (1.97 in): Days with 50 mm or more rain | 12 | 5 | 1952 | 1 |
| 100 mm (3.94 in): Days with 100 mm or more rain | 2 | 1 | 1900 | 1 |
| 10 cm (3.9 in): Days with 10 cm or more snowfall | 3 | 2 | 1954 | 3 |
| 25 cm (9.8 in): Days with 25 cm or more snowfall | 1 | 0 | n/a | 1 |
Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1894.
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).