Philadelphia, PA weather in May
Philadelphia is mild in May, with frequent rain: highs average 74°F and nights drop to about 54°F. Expect about 11 wet days. A great month for outdoor plans.
- Normal high
- 74°F
- Normal low
- 54°F
- Wet days
- 11
- 3.3 in total
- Muggy days
- 2
- dew point 65°F+
How May changes from start to finish
| May 1 | May 31 | |
|---|---|---|
| Normal high | 70°F | 79°F |
| Normal low | 50°F | 59°F |
| Chance of a wet day | 36% | 36% |
| Sunrise / sunset | 6:00 am / 7:54 pm | 5:34 am / 8:22 pm |
| Daylight | 13.9 h | 14.8 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Eastern Time).
A typical May day
- 6 am58°Fdew point 50°F
- 9 am64°Fdew point 50°F
- Noon70°Fdew point 50°F
- 3 pm72°Fdew point 50°F
- 6 pm70°Fdew point 50°F
- 9 pm64°Fdew point 51°F
NOAA hourly normals (local standard time) from Philadelphia Intl Airport (7 mi away); average wind 9 mph; clear or few clouds in 56% of daytime hours, mostly cloudy or overcast in 38%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F16 of 31
- Hot dayshigh 90°F or more2 of 31
- Muggy daysdaily mean dew point 65°F or more2 of 31
- Wet daysat least 0.01 in of rain or melted snow11 of 31
- Notable rainat least 0.10 in6 of 31
- Freezing nightslow 32°F or below0 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per May, counted from daily records for each year 1991-2020.
Rain in May
Normal precipitation is 3.3 in; a dry May brings about 2.4 in and a wet one about 4.0 in (25th and 75th percentiles). About 2 days bring half an inch or more, and about 1 an inch or more.
How May varies from year to year
- Warmest May, 1991-20201991: average high 83°F
- Coolest May2003: average high 68°F
- Wettest May2016: 6.7 in
- Driest May2015: 1.2 in
- Highest reading97°F (May 31, 1991)
- Lowest reading35°F (May 9, 2020)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
May compared with April and June
| April | May | June | |
|---|---|---|---|
| Normal high | 65°F | 74°F | 83°F |
| Normal low | 44°F | 54°F | 64°F |
| Wet days | 11 | 11 | 10 |
| Comfortable days | 13 | 16 | 7 |
| Daylight | 13.3 h | 14.4 h | 15.0 h |
Highs change by +9°F from April and +9°F into June.
Nearby alternatives in May
- Cooler: Stamford, CT114 mi · high 69°F · 12 wet days
How Philadelphia ranks in May
- Normal high202nd warmest of 378 cities; 1st of 4 in Pennsylvania
- Wet days226th driest of 378
- Comfortable days76th most of 339
What to pack for Philadelphia in May
- A rain jacket or umbrella – rain on about 11 days
Heating and cooling
May has 104 heating degree days and 82 cooling degree days (base 65°F), 3% of the year's total heating and cooling demand.
Questions
How hot is Philadelphia in May?
The normal high is 74°F and the normal low is 54°F. From 1991 to 2020 the hottest May reading was 97°F (most recently on May 31, 1991).
Does it rain a lot in Philadelphia in May?
About 11 days in May have at least 0.01 in of precipitation, and the normal total is 3.3 in. The wettest May in 1991-2020 was in 2016 (6.7 in); the driest was in 2015 (1.2 in).
Is May a good time to visit Philadelphia?
May ranks 1st of 12 months on our comfort score for Philadelphia (73 out of 100). It has about 16 comfortable days and about 2 days at 90°F or hotter. The best month is May.
Where the numbers come from
- Temperature, rain, snowfall, snow depth and humidity and wind by hour: Philadelphia Intl Airport (USW00013739), 6.8 mi SSW of the city center, 10 ft . NOAA normals and daily records, 1991-2020.
- Frost dates: Phila Franklin Inst (USC00366886), 0.6 mi NW of the city center, 60 ft . NOAA normals and daily records, 1991-2020.
- Cloud cover: Philadelphia Ne Airport (USW00094732), 12 mi NE of the city center, 100 ft (65 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Philadelphia International Airport (724080-13739), 6.4 mi SSW of the city center, 7 ft . Hourly observations, 1991-2020.