Olney weather in May

In May, Olney sees average daytime highs of 73°F and overnight lows near 56°F, with 3.8 in of rain across 11.3 wet days and about 14.1 hours of daylight. It is the 5th-warmest and 4th-wettest month of the year here.

Highs climb over the month, from about 70°F in the first days to 78°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 36 min at the start of May to 14 h 30 min by month's end. Set against the rest of the year, May is Olney's 12th-clearest and 8th-windiest month. For the whole year in context, see Olney's year-round climate.

Daytime high
73°
5th warmest
Overnight low
56°
8th coldest
Rainfall
3.8 in
11.3 wet days
Daylight
14 h 06 min
5:00 AM – 7:09 PM
Cloud cover
63%
12th clearest
Wind
7 mph
8th windiest
Solar energy
5.71 kWh/m²
Travel score
6.5
out of 10

Olney is census-designated place and unincorporated area in Montgomery County, Maryland, United States, suburb of Washington, DC.

Density
804/km²
people per km²
Founded
1832

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 70°F in the first days to 78°F by the end.

A typical May day in Olney reaches about 73°F in the afternoon and slips back to 56°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 86°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)
16951
26951
37052
47052
57052
67053
77153
87153
97153
107154
117254
127254
137255
147255
157355
167355
177356
187456
197456
207457
217557
227557
237558
247658
257658
267759
277759
287760
297860
307860
317861

How May really feels in Olney

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.

Olney weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan41° / 28°3.18.43.19.60.1
Feb44° / 29°2.98.43.210.50.9
Mar53° / 36°3.910.22.311.73.0
Apr65° / 46°3.410.20.2135.7
May73° / 56°3.811.3014.16.5
Jun82° / 65°3.711.2014.75.7
Jul87° / 69°4.111.6014.54.7
Aug84° / 68°3.610.5013.55.4
Sep78° / 61°4.59.6012.36.9
Oct66° / 49°3.57.80116.4
Nov55° / 39°3.07.60.39.93.7
Dec45° / 32°3.68.91.99.31.1

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 17% of May, with mostly cloudy or overcast conditions the remaining 57%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14357
24456
34456
44456
54456
64357
74357
84456
94357
104258
114357
124357
134357
144357
154357
164258
174258
184357
194357
204258
214258
224258
234357
244357
254357
264357
274456
284357
294357
304456
314357

Chance of precipitation in May

Any precipitation

Olney gets around 3.8 in of rain over 11.3 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 38% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
135
235
335
435
535
635
735
836
936
1037
1137
1237
1337
1437
1537
1637
1737
1838
1938
2038
2138
2238
2337
2437
2537
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 60% of days. Sticky, muggy-or-worse air turns up on roughly 7% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
17914610
27815610
37616710
47517710
57318810
67119820
77019920
86920920
968201020
1067201120
1166201130
1265201230
1364201240
1464191340
1562191450
1661191460
1761181560
1859181670
1957181780
2056171890
2155171990
22531720100
23511720111
24501721121
25481721131
26471722131
27461822141
28451822141
29431922151
30421922161
31412022161

Wind in May

Winds average 7 mph in May.

Across May, daily wind ranges from about 6 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
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm
316calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 36 min at the start of May to 14 h 30 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 5:17 AM to 4:50 AM, and sunset from 6:54 PM to 7:21 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.65:176:54
213.75:166:55
313.75:146:56
413.75:136:57
513.85:126:58
613.85:116:59
713.85:107:00
813.95:097:01
913.95:077:02
1013.95:067:03
1114.05:057:04
1214.05:047:05
1314.05:037:06
1414.15:027:07
1514.15:017:08
1614.15:007:09
1714.25:007:10
1814.24:597:10
1914.24:587:11
2014.34:577:12
2114.34:567:13
2214.34:557:14
2314.34:557:15
2414.44:547:16
2514.44:537:17
2614.44:537:17
2714.44:527:18
2814.54:527:19
2914.54:517:20
3014.54:517:21
3114.54:507:21

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.71 kWh/m².

For context, solar energy here swings from a low near 1.92 kWh/m² to a high of 6.14 kWh/m² in June across the year — May's 5.71 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.5Bright
25.5Bright
35.5Bright
45.5Bright
55.5Bright
65.5Bright
75.5Bright
85.6Bright
95.6Bright
105.6Bright
115.6Bright
125.6Bright
135.6Bright
145.6Bright
155.6Bright
165.7Bright
175.7Bright
185.7Bright
195.7Bright
205.7Bright
215.7Bright
225.8Bright
235.8Bright
245.8Bright
255.8Bright
265.8Bright
275.9Bright
285.9Bright
295.9Bright
305.9Bright
316.0Bright
Planning a trip in May

Hazard calendar for Olney

In seasonPeak

None of Olney's seasonal hazards are active in May. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Olney sits in the Atlantic hurricane belt; the season peaks August–October.

Atlantic hurricane
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is May a good time to visit Olney?

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
4.9
Beach & pool
5th-best month of the year

May is a reasonable time to visit Olney for sightseeing.

What to pack for Olney in May

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

In May, Olney sees daytime highs around 73°F and nights near 56°F. Worth packing: light clothes, rain gear and sun protection. About 11 days see rain.

light clothesrain gearsun protection

Sea temperature near Olney in May

The nearest coast averages about 58°F in May — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 37 mi away) is warmest in August at about 78°F and coldest in February near 36°F.

It's comfortable for a long swim from Jun 16 to Oct 5 — about 3.7 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb36Bracing
Mar40Bracing
Apr47Bracing
May58Bracing
Jun68Refreshing
Jul76Warm
Aug78Warm
Sep74Refreshing
Oct65Cool
Nov53Bracing
Dec44Bracing

UV index in Olney 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 Olney peaks around July 11 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJul 11UV 9Dec 19UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5High
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug7High
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Olney 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 Olney is worst in July — around 17 µg/m³ PM2.5 (moderate), about 1.9× 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
Feb12Moderate
Mar13Moderate
Apr13Moderate
May15Moderate
Jun16Moderate
Jul17Moderate
Aug15Moderate
Sep12Moderate
Oct9Good
Nov9Good
Dec10Good
Location & terrain

Where is Olney?

Olney sits at 39.2°N, 77.1°W, 541 ft above sea level, in United States. The nearest listed city is Redland, 4.3 mi away.

Topography around Olney

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

Within 2 miles, the terrain around Olney has only modest variations in elevation — a maximum elevation change of 256 ft around an average of 476 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 541 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,313 ft.

The land around Olney is covered by trees (72%) and grassland (20%) within 2 miles, trees (68%) within 10 miles, and trees (58%) within 50 miles.

2 miles
256 ft
10 miles
541 ft
50 miles
2,313 ft
treesgrasslandcroplandartificial surfaceswater
May weather nearby: Redland 4.3 mi · Cloverly 5.0 mi · Aspen Hill 5.0 mi · Rockville 6.8 mi · Montgomery Village 6.8 mi · Gaithersburg 7.5 mi · Wheaton 8.1 mi · Fairland 8.1 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 Olney (39.1532°, -77.0669°, elevation 541 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).