Sterling weather in May

In May, Sterling sees average daytime highs of 71°F and overnight lows near 52°F, with 4.7 in of rain across 13.2 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 66°F in the first days to 75°F by the end. The sky is clear or mostly clear about 25% 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 Sterling's 7th-clearest and 8th-windiest month. For the whole year in context, see Sterling's year-round climate.

Daytime high
71°
5th warmest
Overnight low
52°
8th coldest
Rainfall
4.7 in
13.2 wet days
Daylight
14 h 24 min
4:44 AM – 7:06 PM
Cloud cover
65%
7th clearest
Wind
9 mph
8th windiest
Solar energy
5.69 kWh/m²
Travel score
6.0
out of 10

Sterling is city in Whiteside County, Illinois, United States.

Density
978/km²
people per km²
Founded
1838

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 66°F in the first days to 75°F by the end.

A typical May day in Sterling reaches about 71°F in the afternoon and slips back to 52°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 58°F and 83°F. Set against its neighbours, May runs about 11°F warmer than April and about 9°F cooler than June.

40°60°80°151015202531
Avg high (°F)Avg low (°F)
16546
26647
36647
46748
56748
66749
76849
86849
96950
106950
116950
127051
137051
147051
157151
167152
177152
187152
197253
207253
217353
227354
237354
247355
257455
267455
277456
287556
297556
307557
317657

How May really feels in Sterling

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.

Sterling 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
Jan30° / 15°1.97.65.19.30.0
Feb35° / 19°1.96.74.210.30.0
Mar48° / 30°2.69.42.411.71.7
Apr60° / 41°4.311.50.813.14.6
May71° / 52°4.713.2014.36.0
Jun80° / 62°4.5120156.3
Jul83° / 65°3.710.1014.76.0
Aug81° / 63°3.39.1013.76.7
Sep75° / 55°3.48.3012.37.1
Oct62° / 43°2.98.50.210.95.5
Nov47° / 32°2.57.71.39.61.7
Dec35° / 22°2.27.5490.0

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 25% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 14% of May, with mostly cloudy or overcast conditions the remaining 60%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13763
23763
33664
43664
53664
63763
73763
83862
93862
103862
113961
123961
133961
143961
153961
164060
174060
184060
194060
204060
214060
224060
234159
244159
254159
264258
274258
284357
294357
304456
314456

Chance of precipitation in May

Any precipitation

Sterling gets around 4.7 in of rain over 13.2 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 43% and peaks near 44% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
140
241
341
442
543
643
743
844
944
1044
1144
1244
1344
1444
1543
1643
1743
1843
1943
2043
2142
2242
2342
2442
2542
2642
2742
2842
2942
3042
3142

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 (%)
18610310
28610310
38411410
48411410
58212510
68112520
78013520
87913620
97813630
107713730
117614730
127614730
137414840
147414840
157414840
167214950
177214950
1870141060
1970141060
2068151070
2166151180
2265151280
2363161290
2462161390
25601614100
26591714100
27571715110
28561815110
29551915110
30521916121
31512016121

Wind in May

Winds average 9 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
169light breeze
179light breeze
189light breeze
199light breeze
209light 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 5:03 AM to 4:33 AM, and sunset from 6:49 PM to 7:20 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.85:036:49
213.85:016:51
313.95:006:52
413.94:586:53
513.94:576:54
614.04:566:55
714.04:556:56
814.14:536:57
914.14:526:58
1014.14:516:59
1114.24:507:00
1214.24:497:01
1314.24:487:02
1414.34:477:03
1514.34:467:05
1614.44:447:06
1714.44:447:07
1814.44:437:08
1914.44:427:09
2014.54:417:10
2114.54:407:11
2214.54:397:12
2314.64:387:12
2414.64:377:13
2514.64:377:14
2614.74:367:15
2714.74:357:16
2814.74:357:17
2914.74:347:18
3014.84:337:19
3114.84:337:20

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.69 kWh/m².

For context, solar energy here swings from a low near 1.71 kWh/m² to a high of 6.34 kWh/m² in June across the year — May's 5.69 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.3Bright
25.3Bright
35.3Bright
45.4Bright
55.4Bright
65.4Bright
75.5Bright
85.5Bright
95.5Bright
105.6Bright
115.6Bright
125.6Bright
135.7Bright
145.7Bright
155.7Bright
165.7Bright
175.8Bright
185.8Bright
195.8Bright
205.8Bright
215.8Bright
225.8Bright
235.9Bright
245.9Bright
255.9Bright
265.9Bright
275.9Bright
285.9Bright
295.9Bright
306.0Bright
316.0Bright
Planning a trip in May

Is May a good time to visit Sterling?

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
4.0
Beach & pool
5th-best month of the year

May is a reasonable time to visit Sterling for sightseeing.

What to pack for Sterling in May

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

In May, Sterling sees daytime highs around 71°F and nights near 52°F. Worth packing: rain gear and sun protection. About 13 days see rain.

rain gearsun protection

UV index in Sterling 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 Sterling peaks around June 18 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 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJun 18UV 9Dec 19UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul8Very high
Aug8Very high
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Sterling 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 Sterling is worst in July — around 15 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (October, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodModerateGoodJul 1915 µg/m³Oct 227 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb13Moderate
Mar13Moderate
Apr11Good
May13Moderate
Jun13Moderate
Jul15Moderate
Aug14Moderate
Sep11Good
Oct7Good
Nov8Good
Dec9Good
Location & terrain

Where is Sterling?

Sterling sits at 41.8°N, 89.7°W, 659 ft above sea level, in United States. The nearest listed city is Dixon, 12 mi away.

Topography around Sterling

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

Within 2 miles, the terrain around Sterling has only modest variations in elevation — a maximum elevation change of 121 ft around an average of 656 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 295 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 830 ft.

The land around Sterling is covered by trees (28%) and artificial surfaces (28%) within 2 miles, cropland (81%) within 10 miles, and cropland (77%) within 50 miles.

2 miles
121 ft
10 miles
295 ft
50 miles
830 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
May weather nearby: Dixon 12 mi · Clinton 25 mi · Freeport 35 mi · East Moline 43 mi · Rockford 45 mi · Bettendorf 46 mi · Moline 47 mi · Davenport 49 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 Sterling (41.7886°, -89.6962°, elevation 659 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).