Radnor weather in May

In May, Radnor sees average daytime highs of 73°F and overnight lows near 55°F, with 3.5 in of rain across 11.1 wet days and about 14.2 hours of daylight. It is the 5th-warmest and 9th-wettest month of the year here.

Highs climb over the month, from about 69°F in the first days to 77°F by the end. The sky is clear or mostly clear about 26% of the time in May, and the air most often feels dry.

Daylight stretches from about 13 h 42 min at the start of May to 14 h 36 min by month's end. Set against the rest of the year, May is Radnor's 12th-clearest and 8th-windiest month. For the whole year in context, see Radnor's year-round climate.

Daytime high
73°
5th warmest
Overnight low
55°
8th coldest
Rainfall
3.5 in
11.1 wet days
Daylight
14 h 12 min
4:51 AM – 7:04 PM
Cloud cover
63%
12th clearest
Wind
7 mph
8th windiest
Solar energy
5.63 kWh/m²
Travel score
6.5
out of 10

Radnor is unincorporated community in Radnor Township, Pennsylvania, United States.

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 69°F in the first days to 77°F by the end.

A typical May day in Radnor reaches about 73°F in the afternoon and slips back to 55°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 61°F and 85°F. Set against its neighbours, May runs about 9°F warmer than April and about 9°F cooler than June.

40°60°80°151015202531
Avg high (°F)Avg low (°F)
16850
26951
36951
46951
56951
67052
77052
87052
97153
107153
117153
127153
137254
147254
157254
167355
177355
187355
197356
207456
217456
227557
237557
247557
257658
267658
277658
287759
297759
307760
317860

How May really feels in Radnor

Once humidity and wind are folded in, May averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

May sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Radnor weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan40° / 27°3.29.33.89.50.0
Feb43° / 28°3.08.93.410.40.6
Mar52° / 35°4.110.52.611.72.7
Apr64° / 46°3.610.20.3135.5
May73° / 55°3.511.1014.26.5
Jun82° / 64°3.810.7014.85.9
Jul86° / 70°3.910.7014.64.8
Aug84° / 68°3.710.3013.65.5
Sep78° / 61°4.19.2012.36.9
Oct66° / 49°3.68.2010.96.3
Nov55° / 39°2.97.80.39.83.6
Dec45° / 32°3.99.31.99.21.1

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 26% of the time in May, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 19% of May, with mostly cloudy or overcast conditions the remaining 55%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14555
24555
34456
44654
54555
64654
74555
84555
94555
104654
114654
124555
134555
144555
154555
164555
174555
184555
194555
204555
214555
224456
234555
244555
254555
264555
274555
284555
294456
304456
314456

Chance of precipitation in May

Any precipitation

Radnor gets around 3.5 in of rain over 11.1 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 36% and peaks near 37% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
134
234
334
434
535
635
735
835
936
1036
1136
1236
1336
1436
1536
1636
1736
1836
1937
2037
2137
2236
2336
2436
2536
2636
2736
2835
2935
3035
3135

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

Most of May feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, May lands in the dry band about 66% of days. Sticky, muggy-or-worse air turns up on roughly 5% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
18411410
28312410
38113510
48113510
57914610
67914610
77814710
87814710
97615810
107415920
117415920
1273151020
1371151130
1471151130
1569151240
1668151340
1767151350
1865161450
1963161560
2061171660
2160171670
2258171780
2356181880
2454181990
25511820101
26511820101
27491921111
28481921111
29471922111
30452022121
31442022121

Wind in May

Winds average 7 mph in May.

Across May, daily wind ranges from about 7 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 42 min at the start of May to 14 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 54 minutes over May. Sunrise moves from 5:08 AM to 4:41 AM, and sunset from 6:49 PM to 7:17 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.75:086:49
213.75:076:50
313.85:066:51
413.85:056:52
513.85:036:53
613.95:026:54
713.95:016:55
813.95:006:56
914.04:596:57
1014.04:586:58
1114.04:576:59
1214.14:557:00
1314.14:547:01
1414.14:537:02
1514.24:527:03
1614.24:517:04
1714.24:517:05
1814.34:507:06
1914.34:497:07
2014.34:487:08
2114.44:477:09
2214.44:467:09
2314.44:467:10
2414.44:457:11
2514.54:447:12
2614.54:447:13
2714.54:437:14
2814.54:427:15
2914.64:427:15
3014.64:417:16
3114.64:417:17

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.63 kWh/m².

For context, solar energy here swings from a low near 1.82 kWh/m² to a high of 6.03 kWh/m² in June across the year — May's 5.63 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.4Bright
25.4Bright
35.4Bright
45.4Bright
55.5Bright
65.5Bright
75.5Bright
85.5Bright
95.5Bright
105.5Bright
115.5Bright
125.5Bright
135.6Bright
145.6Bright
155.6Bright
165.6Bright
175.6Bright
185.6Bright
195.7Bright
205.7Bright
215.7Bright
225.7Bright
235.7Bright
245.8Bright
255.8Bright
265.8Bright
275.8Bright
285.8Bright
295.9Bright
305.9Bright
315.9Bright
Planning a trip in May

Is May a good time to visit Radnor?

Our two travel scores rate May for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

6.5
Sightseeing
2nd-best month of the year
4.8
Beach & pool
5th-best month of the year

May is a reasonable time to visit Radnor for sightseeing.

What to pack for Radnor in May

From May's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In May, Radnor sees daytime highs around 73°F and nights near 55°F. Worth packing: light clothes, rain gear and sun protection. About 11 days see rain.

light clothesrain gearsun protection

UV index in Radnor in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Radnor peaks around July 10 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJul 10UV 8Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun8Very high
Jul8Very high
Aug6High
Sep6High
Oct3Moderate
Nov3Moderate
Dec2Low

Air quality in Radnor in May

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where May falls, not just the annual average.

Air quality in Radnor is worst in July — around 18 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (November, 9 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1317 µg/m³Nov 129 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb13Moderate
Mar15Moderate
Apr13Moderate
May15Moderate
Jun16Moderate
Jul18Moderate
Aug15Moderate
Sep12Good
Oct9Good
Nov9Good
Dec10Good
Location & terrain

Where is Radnor?

Radnor sits at 40.0°N, 75.4°W, 433 ft above sea level, in United States. The nearest listed city is Wayne, 1.2 mi away.

Topography around Radnor

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Radnor.

Within 2 miles, the terrain around Radnor has only modest variations in elevation — a maximum elevation change of 423 ft around an average of 397 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 981 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,913 ft.

The land around Radnor is covered by trees (80%) within 2 miles, trees (67%) within 10 miles, and trees (58%) within 50 miles.

2 miles
423 ft
10 miles
981 ft
50 miles
1,913 ft
treesgrasslandcroplandartificial surfaceswaterwetland
May weather nearby: Wayne 1.2 mi · King of Prussia 3.7 mi · Havertown 5.0 mi · Norristown 5.6 mi · Overbrook 7.5 mi · Drexel Hill 7.5 mi · Springfield 8.1 mi · Haddington 8.7 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Radnor (40.0462°, -75.3599°, elevation 433 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).