Philadelphia weather in May: Philadelphia, Pennsylvania: normal highs, lows, rain and records for May

Philadelphia in May has a normal high of 74°F and a normal low of 54°F, a daily mean of 64°F, rising from 70°F on the 1st to 79°F by the 31st. Measurable precipitation falls on 11 days in a normal May, 3.34 inches in all. (NOAA 1991-2020 normals)

In metric: a normal high of 24°C and low of 12°C, 85 mm of precipitation in May.

NOAA stationPhiladelphia International Airport
Station IDUSW00013739
Location39.87°N 75.23°W
Elevation10 ft (3 m)
From the center11 miles
Population1,573,916

Jan 41° 26°
Feb 44° 28°
Mar 53° 34°
Apr 65° 44°
May 74° 54°
Jun 83° 64°
Jul 88° 70°
Aug 86° 68°
Sep 79° 61°
Oct 67° 49°
Nov 56° 39°
Dec 46° 31°

Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.

How warm is Philadelphia in May?

The normal high is 74°F and the normal low 54°F, for a daily mean of 64.3°F. May is 9.8°F warmer than April and 9.2°F cooler than June. May is the 5th warmest month of the year in Philadelphia and the 9th wettest. Across the month the normal high rises 9°F, from 70°F on May 1 to 79°F on May 31. From one year to the next May's mean temperature typically moves about 3.0°F either way (NOAA's standard deviation), so roughly two Mays in three average between 61°F and 67°F.

Philadelphia in May, day by day: normal high and low

Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 36%).

Normal high and low on five days of May, with the chance of precipitation
Day	High	Low	Chance of 0.01 in	Chance of 0.10 in
May 1	70°F	50°F	36%	21%
May 8	72°F	52°F	36%	21%
May 15	74°F	54°F	36%	21%
May 22	76°F	56°F	36%	21%
May 31	79°F	59°F	35%	21%

Every day of May: normal high, low and chance of precipitation (warmest afternoon May 31, coldest night May 1)

Philadelphia: NOAA 1991-2020 daily normals for each day of May
Day	High	Low	Chance of 0.01 in	Chance of 0.10 in	Daylight
May 1	70°F	50°F	36%	21%	13 h 50 min
May 2	71°F	50°F	36%	21%	13 h 50 min
May 3	71°F	50°F	36%	21%	14 h
May 4	71°F	51°F	36%	21%	14 h
May 5	72°F	51°F	36%	21%	14 h
May 6	72°F	51°F	36%	21%	14 h
May 7	72°F	52°F	36%	21%	14 h
May 8	72°F	52°F	36%	21%	14 h 10 min
May 9	73°F	52°F	36%	21%	14 h 10 min
May 10	73°F	52°F	36%	21%	14 h 10 min
May 11	73°F	53°F	36%	21%	14 h 10 min
May 12	73°F	53°F	36%	21%	14 h 10 min
May 13	74°F	53°F	36%	21%	14 h 20 min
May 14	74°F	54°F	36%	21%	14 h 20 min
May 15	74°F	54°F	36%	21%	14 h 20 min
May 16	74°F	54°F	36%	21%	14 h 20 min
May 17	75°F	55°F	36%	21%	14 h 20 min
May 18	75°F	55°F	36%	21%	14 h 30 min
May 19	75°F	55°F	36%	21%	14 h 30 min
May 20	75°F	55°F	36%	21%	14 h 30 min
May 21	76°F	56°F	36%	21%	14 h 30 min
May 22	76°F	56°F	36%	21%	14 h 30 min
May 23	76°F	56°F	36%	21%	14 h 30 min
May 24	77°F	57°F	36%	21%	14 h 40 min
May 25	77°F	57°F	36%	21%	14 h 40 min
May 26	77°F	57°F	36%	21%	14 h 40 min
May 27	77°F	58°F	36%	21%	14 h 40 min
May 28	78°F	58°F	36%	21%	14 h 40 min
May 29	78°F	58°F	36%	21%	14 h 40 min
May 30	78°F	59°F	36%	21%	14 h 40 min
May 31	79°F	59°F	35%	21%	14 h 50 min

Normal high: 74°FMay average
Normal low: 54°FMay average
Precipitation: 3.34 inmonth total
Days with precipitation: 110.01 inch or more
Days at 90°F or more: 2
Daylight: 13 h 50 min to 14 h 50 minMay 1 to May 31
Days at 70°F or more: 21
Days at 80°F or more: 10
Sunshine: 72%of clear-sky sunlight (NASA)

Source: NOAA NCEI 1991-2020 daily normals, station USW00013739; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.

Does it rain in Philadelphia in May?

On a given May day the chance of 0.01 inch or more is 36% on average, highest around May 10 (36%). In all, 3.34 in falls on 11 days of a normal May, 1 of them with an inch or more.

In a normal May in Philadelphia, 2 days reach 90°F.

Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00013739.

How humid and windy is Philadelphia in May?

At 3 p.m. the normal temperature is 77°F with 47% relative humidity and a dew point of 55°F; at 6 a.m. it is 63°F with 79% humidity. The wind averages 8.6 mph, most often from the west-southwest in the afternoon.

A normal May day at the station, hour by hour (local standard time)
Time	Temperature	Dew point	Humidity	Wind	Clear or few clouds
6 a.m.	63°F	56°F	79%	6.7 mph	24%
9 a.m.	70°F	56°F	62%	8.9 mph	27%
noon	75°F	56°F	51%	9.9 mph	21%
3 p.m.	77°F	55°F	47%	11.1 mph	–
6 p.m.	75°F	56°F	51%	10.5 mph	–
9 p.m.	69°F	57°F	66%	8.1 mph	31%

Source: NOAA NCEI 1991-2020 hourly normals, station USW00013739. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).

What are the records for May in Philadelphia?

The warmest May temperature on Philadelphia's official record (since 1873) is 98°F, on May 19, 2026; the coldest is 28°F, on May 11, 1966. The wettest May brought 9.46 in (1894).

The May mean against the 1991-2020 normal of 64.3°F: 2021 64.1°F (−0.2), 2022 67.5°F (+3.2), 2023 62.4°F (−1.9), 2024 66.5°F (+2.3), 2025 65.3°F (+1.0), 2026 65.6°F (+1.3). 4 of 6 ran warmer than normal.

Philadelphia: May in recent years against the 1991-2020 normal
May	Mean	Against normal	Precip.
2021	64.1°F	−0.2°F	3.24 in
2022	67.5°F	+3.2°F	4.16 in
2023	62.4°F	−1.9°F	0.24 in
2024	66.5°F	+2.3°F	1.72 in
2025	65.3°F	+1.0°F	6.22 in
2026	65.6°F	+1.3°F	2.77 in

Source: records: ACIS, NWS threaded record PHLthr; recent months: ACIS, station USW00013739. Records and recent months use complete months only.

How does May in Philadelphia compare across Pennsylvania?

Across the 108 places PlainClimate covers in Pennsylvania, May normal highs run from 65°F in Laporte to 75°F in Phoenixville; Philadelphia's is 74°F.

Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.

How warm is Philadelphia in May?

Does it rain in Philadelphia in May?

How humid and windy is Philadelphia in May?

What are the records for May in Philadelphia?

How does May in Philadelphia compare across Pennsylvania?

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