| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Record high °F (°C) | 74 (23) |
79 (26) |
87 (31) |
95 (35) |
97 (36) |
102 (39) |
104 (40) |
106 (41) |
102 (39) |
96 (36) |
84 (29) |
73 (23) |
106 (41) |
| Mean maximum °F (°C) | 63.3 (17.4) |
63.5 (17.5) |
73.8 (23.2) |
84.3 (29.1) |
90.2 (32.3) |
94.8 (34.9) |
97.1 (36.2) |
94.8 (34.9) |
90.6 (32.6) |
82.6 (28.1) |
72.4 (22.4) |
64.2 (17.9) |
98.1 (36.7) |
| Mean daily maximum °F (°C) | 41.3 (5.2) |
44.3 (6.8) |
52.8 (11.6) |
64.7 (18.2) |
74.4 (23.6) |
83.2 (28.4) |
87.8 (31.0) |
85.8 (29.9) |
78.9 (26.1) |
67.2 (19.6) |
55.9 (13.3) |
46.0 (7.8) |
65.2 (18.4) |
| Daily mean °F (°C) | 33.7 (0.9) |
35.9 (2.2) |
43.6 (6.4) |
54.5 (12.5) |
64.3 (17.9) |
73.5 (23.1) |
78.7 (25.9) |
76.8 (24.9) |
69.9 (21.1) |
58.2 (14.6) |
47.4 (8.6) |
38.6 (3.7) |
56.3 (13.5) |
| Mean daily minimum °F (°C) | 26.0 (−3.3) |
27.5 (−2.5) |
34.3 (1.3) |
44.3 (6.8) |
54.2 (12.3) |
63.9 (17.7) |
69.6 (20.9) |
67.9 (19.9) |
60.9 (16.1) |
49.2 (9.6) |
38.8 (3.8) |
31.2 (−0.4) |
47.3 (8.5) |
| Mean minimum °F (°C) | 10.7 (−11.8) |
13.7 (−10.2) |
20.8 (−6.2) |
33.0 (0.6) |
43.1 (6.2) |
53.2 (11.8) |
62.2 (16.8) |
60.3 (15.7) |
49.5 (9.7) |
37.1 (2.8) |
26.4 (−3.1) |
19.0 (−7.2) |
8.6 (−13.0) |
| Record low °F (°C) | −7 (−22) |
−11 (−24) |
5 (−15) |
14 (−10) |
28 (−2) |
44 (7) |
51 (11) |
44 (7) |
35 (2) |
25 (−4) |
8 (−13) |
−5 (−21) |
−11 (−24) |
| Average precipitation inches (mm) | 3.13 (80) |
2.75 (70) |
3.96 (101) |
3.47 (88) |
3.34 (85) |
4.04 (103) |
4.38 (111) |
4.29 (109) |
4.40 (112) |
3.47 (88) |
2.91 (74) |
3.97 (101) |
44.11 (1,120) |
| Average snowfall inches (cm) | 7.1 (18) |
8.4 (21) |
3.6 (9.1) |
0.3 (0.76) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.2 (0.51) |
3.5 (8.9) |
23.1 (59) |
| Average precipitation days (≥ 0.01 in) | 11.0 | 9.7 | 10.9 | 10.9 | 11.0 | 10.3 | 10.1 | 8.9 | 9.3 | 9.1 | 8.6 | 11.0 | 120.8 |
| Average snowy days (≥ 0.1 in) | 4.1 | 3.8 | 2.0 | 0.2 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 1.8 | 12.0 |
| Average relative humidity (%) | 66.2 | 63.6 | 61.7 | 60.4 | 65.4 | 67.8 | 69.6 | 70.4 | 71.6 | 70.8 | 68.4 | 67.7 | 67.0 |
| Average dew point °F (°C) | 19.8 (−6.8) |
21.0 (−6.1) |
28.6 (−1.9) |
37.0 (2.8) |
49.5 (9.7) |
59.2 (15.1) |
64.6 (18.1) |
63.7 (17.6) |
57.2 (14.0) |
45.7 (7.6) |
35.6 (2.0) |
25.5 (−3.6) |
42.3 (5.7) |
| Mean monthly sunshine hours | 155.7 | 154.7 | 202.8 | 217.0 | 245.1 | 271.2 | 275.6 | 260.1 | 219.3 | 204.5 | 154.7 | 137.7 | 2,498.4 |
| Percent possible sunshine | 52 | 52 | 55 | 55 | 55 | 61 | 61 | 61 | 59 | 59 | 52 | 47 | 56 |
| Average ultraviolet index | 2 | 3 | 4 | 6 | 8 | 9 | 9 | 8 | 6 | 4 | 2 | 2 | 5 |
| Source 1: NOAA (relative humidity, dew point and sun 1961–1990)[4][5][2] | |||||||||||||
| Source 2: Weather Atlas (UV index)[6] | |||||||||||||
| Climate data for Philadelphia | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Average sea temperature °F (°C) | 41.8 (5.5) |
39.9 (4.4) |
41.2 (5.1) |
46.7 (8.2) |
53.9 (12.2) |
66.3 (19.0) |
74.0 (23.3) |
75.9 (24.4) |
71.4 (21.9) |
64.2 (17.9) |
55.1 (12.8) |
47.7 (8.8) |
56.5 (13.6) |
| Mean daily daylight hours | 10.0 | 11.0 | 12.0 | 13.0 | 14.0 | 15.0 | 15.0 | 14.0 | 12.0 | 11.0 | 10.0 | 9.0 | 12.2 |
| Source: Weather Atlas [6] | |||||||||||||
Notes
- ^ Mean monthly maxima and minima (i.e. the highest and lowest temperature readings during an entire month or year) calculated based on data at said location from 1991 to 2020.
- ^ Official temperature and precipitation measurements for Philadelphia were taken at the Weather Bureau Office in downtown from January 1872 to 19 June 1940, and at Philadelphia Int'l from 20 June 1940 to the present.[1] Snowfall and snow depth records date to 1 January 1884 and 1 October 1948, respectively.[2] In 2006, snowfall measurements were moved to National Park, New Jersey directly across the Delaware River from the airport.[3]
References
- ^ ThreadEx; search for location= "PA - Philadelphia", variable= "Station thread"
- ^ a b "NowData – NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Retrieved April 13, 2016.
- ^ Wood, Anthony R. "Snow total at airport gets a boost A new measuring station and technique likely contributed to two 8-inch-plus readings". Philly.com. The Inquirer. Archived from the original on 2014-07-28. Retrieved 2014-06-10.
- ^ "Summary of Monthly Normals 1991–2020". National Oceanic and Atmospheric Administration. Retrieved June 13, 2021.
- ^ "WMO Climate Normals for PHILADELPHIA/INT'L ARPT PA 1961–1990". National Oceanic and Atmospheric Administration. Retrieved July 18, 2020.
- ^ a b "Philadelphia, Pennsylvania, USA - Monthly weather forecast and Climate data". Weather Atlas. Retrieved May 17, 2019.