Oak Forest weather in May

In May, Oak Forest sees average daytime highs of 70°F and overnight lows near 51°F, with 4.6 in of rain across 12.6 wet days and about 14.3 hours of daylight. It is the 5th-warmest and 1st-wettest month of the year here.

Highs climb over the month, from about 65°F in the first days to 74°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 48 min at the start of May to 14 h 48 min by month's end. Set against the rest of the year, May is Oak Forest's 6th-clearest and 8th-windiest month. For the whole year in context, see Oak Forest's year-round climate.

Daytime high
70°
5th warmest
Overnight low
51°
8th coldest
Rainfall
4.6 in
12.6 wet days
Daylight
14 h 18 min
4:37 AM – 6:57 PM
Cloud cover
64%
6th clearest
Wind
8 mph
8th windiest
Solar energy
5.89 kWh/m²
Travel score
6.0
out of 10

Oak Forest is city in Cook County, Illinois, United States.

Density
1,807/km²
people per km²
Founded
1800

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 65°F in the first days to 74°F by the end.

A typical May day in Oak Forest reaches about 70°F in the afternoon and slips back to 51°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 56°F and 83°F. Set against its neighbours, May runs about 10°F warmer than April and about 10°F cooler than June.

40°60°80°151015202531
Avg high (°F)Avg low (°F)
16446
26547
36547
46647
56648
66648
76748
86749
96749
106849
116850
126850
136950
146951
156951
167051
177051
187052
197152
207153
217153
227253
237254
247354
257355
267355
277355
287456
297456
307456
317557

How May really feels in Oak Forest

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.

Oak Forest weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan32° / 19°2.38.75.79.30.0
Feb36° / 21°2.07.14.810.30.0
Mar47° / 31°2.910.6311.71.5
Apr59° / 41°4.412.60.913.14.3
May70° / 51°4.612.6014.36.0
Jun79° / 62°4.311.60156.3
Jul83° / 66°3.911.9014.75.8
Aug81° / 64°3.810.8013.76.5
Sep75° / 56°3.08.5012.37.1
Oct62° / 44°3.29.50.110.95.4
Nov48° / 34°2.78.61.29.71.9
Dec37° / 24°2.283.990.0

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 26% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 15% of May, with mostly cloudy or overcast conditions the remaining 59%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13862
23862
33763
43862
53862
63862
73862
83961
93961
103961
113961
124060
134159
144159
154258
164258
174258
184357
194357
204357
214357
224456
234456
244456
254357
264357
274456
284456
294456
304456
314456

Chance of precipitation in May

Any precipitation

Oak Forest gets around 4.6 in of rain over 12.6 wet days in May, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 41% and peaks near 41% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
141
241
341
441
541
641
741
841
941
1041
1141
1241
1341
1441
1541
1641
1741
1841
1941
2041
2141
2240
2340
2440
2541
2641
2741
2840
2940
3040
3140

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 71% of days. Sticky, muggy-or-worse air turns up on roughly 6% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1889210
28710210
38511310
48511310
58212420
68212420
78013520
88013520
97813630
107714630
117614730
127514740
137415740
147315840
157315840
167115950
177016950
1868161060
1968161060
2067161070
2166161170
2264161280
2363171280
2461171390
2561171390
26601713100
27581714101
28561814111
29551815111
30541815121
31531915121

Wind in May

Winds average 8 mph in May.

Across May, daily wind ranges from about 8 mph on the calmest days to 9 mph at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (mph)Feels
19light breeze
29light breeze
39light breeze
49light breeze
59light breeze
69light breeze
79light breeze
89light breeze
99light breeze
109light breeze
119light breeze
129light breeze
139light breeze
149light breeze
159light breeze
168light breeze
178light breeze
188light breeze
198light breeze
208light breeze
218light breeze
228light breeze
238light breeze
248light breeze
258light breeze
268light breeze
278light breeze
288light breeze
298light breeze
308light breeze
318light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 48 min at the start of May to 14 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 60 minutes over May. Sunrise moves from 4:55 AM to 4:26 AM, and sunset from 6:41 PM to 7:11 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.84:556:41
213.84:546:42
313.94:526:43
413.94:516:45
513.94:506:46
614.04:486:47
714.04:476:48
814.04:466:49
914.14:456:50
1014.14:446:51
1114.24:426:52
1214.24:416:53
1314.24:406:54
1414.34:396:55
1514.34:386:56
1614.34:376:57
1714.44:366:58
1814.44:356:59
1914.44:347:00
2014.54:337:01
2114.54:337:02
2214.54:327:03
2314.64:317:04
2414.64:307:05
2514.64:297:06
2614.64:297:07
2714.74:287:08
2814.74:277:09
2914.74:277:09
3014.74:267:10
3114.84:267:11

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.89 kWh/m².

For context, solar energy here swings from a low near 1.66 kWh/m² to a high of 6.5 kWh/m² in June across the year — May's 5.89 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.5Bright
25.5Bright
35.5Bright
45.6Bright
55.6Bright
65.6Bright
75.6Bright
85.7Bright
95.7Bright
105.7Bright
115.8Bright
125.8Bright
135.8Bright
145.8Bright
155.9Bright
165.9Bright
175.9Bright
186.0Bright
196.0Bright
206.0Intense
216.0Intense
226.0Intense
236.1Intense
246.1Intense
256.1Intense
266.1Intense
276.1Intense
286.2Intense
296.2Intense
306.2Intense
316.2Intense
Planning a trip in May

Is May a good time to visit Oak Forest?

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

6.0
Sightseeing
4th-best month of the year
3.7
Beach & pool
5th-best month of the year

May is a reasonable time to visit Oak Forest for sightseeing.

What to pack for Oak Forest in May

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

In May, Oak Forest sees daytime highs around 70°F and nights near 51°F. Worth packing: rain gear and sun protection. About 13 days see rain.

rain gearsun protection

Sea temperature near Oak Forest in May

The nearest coast averages about 46°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 19 mi away) is warmest in August at about 73°F and coldest in February near 35°F.

It's comfortable for a long swim from Jul 10 to Sep 16 — about 2.3 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb35Bracing
Mar35Bracing
Apr39Bracing
May46Bracing
Jun59Cool
Jul70Refreshing
Aug73Refreshing
Sep68Refreshing
Oct58Bracing
Nov49Bracing
Dec42Bracing

UV index in Oak Forest in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Oak Forest peaks around June 23 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 2 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 23UV 9Jan 1UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun9Very high
Jul9Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Oak Forest 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 Oak Forest is worst in July — around 18 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 8 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1418 µg/m³Oct 238 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar15Moderate
Apr15Moderate
May17Moderate
Jun17Moderate
Jul18Moderate
Aug16Moderate
Sep12Moderate
Oct8Good
Nov9Good
Dec10Good
Location & terrain

Where is Oak Forest?

Oak Forest sits at 41.6°N, 87.7°W, 673 ft above sea level, in United States. The nearest listed city is Country Club Hills, 2.5 mi away.

Topography around Oak Forest

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

Within 2 miles, the terrain around Oak Forest has only modest variations in elevation — a maximum elevation change of 164 ft around an average of 673 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 541 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 741 ft.

The land around Oak Forest is covered by trees (43%) and artificial surfaces (35%) within 2 miles, artificial surfaces (40%) and trees (35%) within 10 miles, and cropland (38%) and water (21%) within 50 miles.

2 miles
164 ft
10 miles
541 ft
50 miles
741 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
May weather nearby: Country Club Hills 2.5 mi · Tinley Park 3.1 mi · Alsip 4.3 mi · Blue Island 5.0 mi · Harvey 5.0 mi · Homewood 5.0 mi · Orland Park 6.2 mi · Mount Greenwood 6.8 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 Oak Forest (41.6028°, -87.7439°, elevation 673 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. 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).