Philadelphia, PA climate: monthly averages and frost dates
Philadelphia, PA has cool winters and warm summers by this site's scale, with wet annual precipitation. The figures are the 1991–2020 climate normals for NOAA station USW00013739 (PHILADELPHIA INTL AP), 11 mi (18 km) in a straight line from the city's center point (US Census).
- Warmest month high
- 87.8°F
- July
- Coldest month mean
- 33.7°F
- January
- Precipitation
- 44.1 in
- per year
- Snowfall
- 23.1 in
- per year
- Median last frost
- April 2
- 32°F, spring
- Median first frost
- November 10
- 32°F, autumn
Monthly averages in Philadelphia
| Month | High °F | Low °F | Mean °F | Precip. in | Snow in | Days ≥0.01 in | Days ≥90°F | Nights ≤32°F |
|---|---|---|---|---|---|---|---|---|
| January | 41.3 | 26.0 | 33.7 | 3.13 | 7.1 | 11.0 | 0.0 | 22.5 |
| February | 44.3 | 27.5 | 35.9 | 2.75 | 8.4 | 9.7 | 0.0 | 19.6 |
| March | 52.8 | 34.3 | 43.6 | 3.96 | 3.6 | 10.9 | 0.0 | 11.8 |
| April | 64.7 | 44.3 | 54.5 | 3.47 | 0.3 | 10.9 | 0.2 | 0.8 |
| May | 74.4 | 54.2 | 64.3 | 3.34 | 0.0 | 11.0 | 1.7 | 0.0 |
| June | 83.2 | 63.9 | 73.5 | 4.04 | 0.0 | 10.3 | 5.8 | 0.0 |
| July | 87.8 | 69.6 | 78.7 | 4.38 | 0.0 | 10.1 | 12.5 | 0.0 |
| August | 85.8 | 67.9 | 76.8 | 4.29 | 0.0 | 8.9 | 7.5 | 0.0 |
| September | 78.9 | 60.9 | 69.9 | 4.40 | 0.0 | 9.3 | 1.9 | 0.0 |
| October | 67.2 | 49.2 | 58.2 | 3.47 | 0.0 | 9.1 | 0.0 | 0.1 |
| November | 55.9 | 38.8 | 47.4 | 2.91 | 0.2 | 8.6 | 0.0 | 5.4 |
| December | 46.0 | 31.2 | 38.6 | 3.97 | 3.5 | 11.0 | 0.0 | 17.2 |
| Year | 65.2 | 47.3 | 56.3 | 44.11 | 23.1 | 120.8 | 29.7 | 77.3 |
How cold is winter in Philadelphia?
Winters in Philadelphia are cool by this site's scale (coldest-month mean 32 to under 45°F). The coldest month is January, with a mean temperature of 33.7°F (0.9°C), a normal daily high of 41.3°F (5.2°C) and a normal daily low of 26.0°F (−3.3°C).
The station averages 77.3 nights a year at or below 32°F and 13.1 days when the high stays at or below 32°F.
The normal daily low is at or below freezing in December to February.
How hot is summer in Philadelphia?
Summers in Philadelphia are warm by this site's scale (hottest-month high 80 to under 90°F). July has the highest normal daily high, 87.8°F (31.0°C), with nights averaging 69.6°F (20.9°C).
The high reaches 90°F or more on 29.7 days in a normal year.
What is the wettest month in Philadelphia?
Philadelphia gets 44.11 in (1120 mm) of precipitation in a normal year, which this site classes as wet (40 to under 60 in a year). The wettest month is September with 4.40 in (112 mm); the driest is February with 2.75 in (70 mm).
Measurable precipitation (0.01 in or more) falls on 120.8 days a year.
Does it snow in Philadelphia?
Normal annual snowfall in Philadelphia is 23.1 in (59 cm), which this site classes as moderate (12 to under 36 in a year).
February is the snowiest month, with 8.4 in (21 cm).
A day with 1.0 in or more of snowfall comes 5.2 times a year on average.
Which months are mild in Philadelphia?
4 months in Philadelphia meet this site's comfort thresholds (normal high 65–85°F, low 45°F or higher, fewer than 10 days with 0.10 in or more of precipitation): May, June, September and October.
August misses by one threshold only (normal high 85.8°F, above the 85°F limit).
Thresholds and their limits: methodology.
Frost dates and growing season in Philadelphia
In Philadelphia the median last spring night at or below 32°F is April 2, and the median first autumn one is November 10 (NOAA P50 dates). NOAA's median length of the freeze-free season is 224 days. NOAA takes that median over each year's own season, so it need not equal the 222 days between the two median dates.
There is still a 10% chance of a 32°F night on or after April 13, and a 10% chance that the first one has come by October 30.
The chance that the last spring 32°F night comes on or after March 19 is 90%.
For a hard freeze (28°F or lower) the median dates are March 22 in spring and November 23 in autumn.
| Chance | Last spring 32°F night on or after | First autumn 32°F night by | Freeze-free season, days |
|---|---|---|---|
| 10% | April 13 | October 30 | 243 |
| 20% | April 8 | November 2 | 236 |
| 30% | April 6 | November 5 | 232 |
| 40% | April 3 | November 8 | 228 |
| 50% | April 2 | November 10 | 224 |
| 60% | March 31 | November 13 | 220 |
| 70% | March 29 | November 16 | 217 |
| 80% | March 24 | November 19 | 212 |
| 90% | March 19 | November 24 | 207 |
| Threshold | Median last date (spring) | Median first date (autumn or winter) | Median season, days |
|---|---|---|---|
| 36°F | April 13 | October 31 | 200 |
| 32°F | April 2 | November 10 | 224 |
| 28°F | March 22 | November 23 | 246 |
| 24°F | March 12 | December 4 | 269 |
| 20°F | March 1 | December 21 | 294 |
| 16°F | February 13 | January 4 | 318 |
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 100% | 100% | 100% | 58% | 0% | 0% | 0% | 0% | 0% | 14% | 94% | 99% |
Nearby and similar places
Of the places on this site, the closest to Philadelphia by station distance are New York, NY at 92 mi (147 km), Washington, DC at 119 mi (192 km) and Boston, MA at 279 mi (449 km).
Among places whose winter, summer and precipitation words are each within one band of Philadelphia's (winter: cool, summer: warm, precipitation: wet), the closest monthly temperature and precipitation patterns are New York, NY, Washington, DC and Charlotte, NC.
Compared with New York, NY, Philadelphia's peak-month normal high is 2.9°F (1.6°C) higher, its coldest-month mean is about the same, and its annual precipitation is 5.41 in less.
| Place | Listed as | Station distance | Coldest mean °F | Warmest high °F | Precip. in/yr | Snow in/yr | Last frost |
|---|---|---|---|---|---|---|---|
| Philadelphia, PA | this page | – | 33.7 | 87.8 | 44.1 | 23.1 | April 2 |
| New York, NY | nearby, similar | 92 mi (147 km) | 33.7 | 84.9 | 49.5 | 29.8 | March 30 |
| Washington, DC | nearby, similar | 119 mi (192 km) | 37.5 | 89.6 | 41.8 | 13.7 | March 24 |
| Boston, MA | nearby | 279 mi (449 km) | 29.9 | 82.1 | 43.6 | 49.2 | April 4 |
| Charlotte, NC | similar | 448 mi (722 km) | 42.1 | 90.3 | 43.6 | 3.5 | March 30 |
How nearby and similar places are chosen: methodology.
Source and station
The data for Philadelphia come from NOAA station PHILADELPHIA INTL AP, PA US (USW00013739) at 39.8683, -75.2311, elevation 10 ft (3 m). It lies 11 mi (18 km) in a straight line from the center point of Philadelphia city, the “internal point” in the US Census 2024 Gazetteer.
Each monthly normal used here rests on at least 29 years of data from 1991–2020 (NOAA's per-field year counts).
NOAA completeness flags on the monthly fields used here:
- S: Standard: meets WMO standards for data availability for 24 or more years.
Cite the data as:
Palecki, Michael; Durre, Imke; Applequist, Scott; Arguez, Anthony; Lawrimore, Jay (2021). U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991-2020). Station USW00013739 (PHILADELPHIA INTL AP, PA US). NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.25921/wck8-er13. Accessed 2026-10-09.
Palecki, Michael; Durre, Imke; Applequist, Scott; Arguez, Anthony; Lawrimore, Jay (2021). U.S. Climate Normals 2020: U.S. Annual/Seasonal Climate Normals (1991-2020). Station USW00013739 (PHILADELPHIA INTL AP, PA US). NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.25921/4ek7-fk11. Accessed 2026-10-09.
Files used: monthly normals CSV, annual/seasonal normals CSV (retrieved 2026-10-09). The values on this page as JSON: /us/pa/philadelphia/data.json.