Philadelphia Threshold Days by Year (USC00306557)

16 fixed thresholds counted per year at Philadelphia (USC00306557): hot days, frost, tropical nights and heavy rain, with the most days in a year.

Key Facts for Philadelphia Thresholds

Philadelphia: days with a maximum temperature at or above 30 C (86 F) in 25 years, most in 1921 with 30.
Philadelphia: days with a maximum temperature at or below 0 C (32 F) in 25 years, most in 1914 with 78.
Philadelphia: nights with a minimum temperature at or below 0 C (32 F) in 25 years, most in 1924 with 171.
Philadelphia: nights with a minimum temperature at or below -10 C (14 F) in 25 years, most in 1917 with 79.
16 fixed thresholds have at least one qualifying day at Philadelphia.

Days at or above 30 C (86 F)

25 years with a qualifying day

Days per year at Philadelphia with a maximum temperature at or above 30 C (86 F), with the decade average as a line. The most was 30 in 1921.

Days at or above 30 C (86 F) per year at Philadelphia
Year	Days	Decade average
1908	13	12.5
1909	12	12.5
1910	9	13.4
1911	19	13.4
1912	13	13.4
1913	25	13.4
1914	12	13.4
1915	2	13.4
1916	23	13.4
1917	8	13.4
1918	14	13.4
1919	9	13.4
1920	1	12.8
1921	30	12.8
1922	13	12.8
1923	13	12.8
1924	7	12.8
1925	15	12.8
1926	8	12.8
1927	16	12.8
1928	13	12.8
1929	12	12.8
1931	11	11
1932	6	11
1933	16	11

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

First to last qualifying date each year at Philadelphia
Year	First date	Last date
1908	1908-05-28	1908-09-26
1909	1909-06-27	1909-09-23
1910	1910-07-03	1910-08-26
1911	1911-05-11	1911-08-03
1912	1912-07-03	1912-07-16
1913	1913-04-25	1913-09-02
1914	1914-06-24	1914-09-22
1915	1915-09-14	1915-09-15
1916	1916-07-12	1916-09-07
1917	1917-07-23	1917-08-02
1918	1918-07-21	1918-08-23
1919	1919-06-02	1919-07-04
1920	1920-08-09	1920-08-09
1921	1921-06-10	1921-09-29
1922	1922-06-24	1922-09-11
1923	1923-06-18	1923-09-02
1924	1924-06-20	1924-08-31
1925	1925-06-03	1925-09-11
1926	1926-07-05	1926-08-13
1927	1927-06-10	1927-08-22
1928	1928-05-05	1928-08-29
1929	1929-05-30	1929-09-05
1931	1931-06-20	1931-09-22
1932	1932-07-26	1932-09-01
1933	1933-06-11	1933-08-15

Every Fixed Threshold

Fixed thresholds at Philadelphia
Threshold	Years with a qualifying day	Most days in a year	Year	Latest year days
30 C (86 F): Days	25	30	1921	16
35 C (95 F): Days	5	2	1911	1
90 F (32.2 C): Days	20	11	1921	7
0 C (32 F): Ice days (max	25	78	1914	46
0 C (32 F): Frost days (min	25	171	1924	165
-10 C (14 F): Days with min	25	79	1917	54
-20 C (-4 F): Days with min	25	30	1917	16
-30 C (-22 F): Days with min	20	9	1917	2
-40 C (-40 F): Days with min	2	1	1925	1
20 C (68 F): Tropical nights (min	23	12	1921	6
25 C (77 F): Days with min	3	2	1911	2
10 mm (0.39 in): Days with 10 mm or more rain	18	42	1918	25
25 mm (0.98 in): Days with 25 mm or more rain	18	10	1925	1
50 mm (1.97 in): Days with 50 mm or more rain	8	2	1920	2
10 cm (3.9 in): Days with 10 cm or more snowfall	2	15	1926	15
25 cm (9.8 in): Days with 25 cm or more snowfall	2	2	1926	2

Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1908.

Download the Data

Data for Philadelphia 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).

Philadelphia Threshold Days by Year (USC00306557)

Key Facts for Philadelphia Thresholds

Days at or above 30 C (86 F)

Every Fixed Threshold

Download the Data

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