Freeport weather in May

In May, Freeport sees average daytime highs of 69°F and overnight lows near 50°F, with 4.4 in of rain across 13.1 wet days and about 14.4 hours of daylight. It is the 5th-warmest and 1st-wettest month of the year here.

Highs climb over the month, from about 64°F in the first days to 74°F by the end. The sky is clear or mostly clear about 24% 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 Freeport's 8th-clearest and 8th-windiest month. For the whole year in context, see Freeport's year-round climate.

Daytime high
69°
5th warmest
Overnight low
50°
8th coldest
Rainfall
4.4 in
13.1 wet days
Daylight
14 h 24 min
4:43 AM – 7:07 PM
Cloud cover
65%
8th clearest
Wind
8 mph
8th windiest
Solar energy
5.7 kWh/m²
Travel score
5.9
out of 10

Freeport is city and county seat and largest city of Stephenson County, Illinois, United States.

Density
802/km²
people per km²
Founded
1827

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 64°F in the first days to 74°F by the end.

A typical May day in Freeport reaches about 69°F in the afternoon and slips back to 50°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 57°F and 81°F. Set against its neighbours, May runs about 11°F warmer than April and about 10°F cooler than June.

40°60°80°151015202531
Avg high (°F)Avg low (°F)
16445
26445
36446
46546
56547
66647
76647
86648
96748
106748
116749
126849
136849
146950
156950
166950
176951
187051
197051
207152
217152
227152
237253
247253
257253
267354
277354
287355
297455
307455
317456

How May really feels in Freeport

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.

Freeport 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
Jan29° / 15°1.87.55.89.30.0
Feb33° / 18°1.86.65.110.30.0
Mar46° / 29°2.69.52.911.61.2
Apr58° / 39°4.311.91.113.14.0
May69° / 50°4.413.1014.45.9
Jun79° / 60°4.3120156.3
Jul82° / 64°3.610.4014.86.4
Aug80° / 62°3.79.9013.76.7
Sep73° / 54°3.68.8012.37.0
Oct60° / 42°2.98.80.210.85.0
Nov46° / 31°2.47.81.79.61.3
Dec34° / 21°2.17.64.690.0

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 24% 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 61%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13565
23664
33664
43565
53565
63763
73763
83763
93763
103763
113763
123961
133961
143961
153961
164060
173961
183961
193961
203961
213961
224060
234060
244060
254060
264258
274258
284159
294258
304258
314357

Chance of precipitation in May

Any precipitation

Freeport gets around 4.4 in of rain over 13.1 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 42% and peaks near 44% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
141
242
342
443
543
644
744
844
944
1043
1143
1243
1343
1443
1542
1642
1742
1842
1942
2041
2141
2241
2341
2441
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 74% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)
190721
289821
388831
487931
587931
6851041
7841042
8821152
9821152
10811162
11801262
12791272
13781273
14771283
15771283
16751384
17741394
18741394
19731395
207014106
217014106
226814117
236715117
246515128
256416128
266216139
276117139
286117139
2958181410
3058181410
3155191511

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
68light breeze
78light breeze
88light breeze
98light breeze
108light breeze
118light breeze
128light breeze
138light breeze
148light breeze
158light 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 5:01 AM to 4:31 AM, and sunset from 6:50 PM to 7:21 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.85:016:50
213.95:006:51
313.94:586:52
413.94:576:54
514.04:566:55
614.04:556:56
714.14:536:57
814.14:526:58
914.14:516:59
1014.24:507:00
1114.24:487:01
1214.34:477:02
1314.34:467:03
1414.34:457:04
1514.44:447:06
1614.44:437:07
1714.44:427:08
1814.54:417:09
1914.54:407:10
2014.54:397:11
2114.64:387:12
2214.64:377:13
2314.64:367:14
2414.64:367:15
2514.74:357:16
2614.74:347:16
2714.74:337:17
2814.84:337:18
2914.84:327:19
3014.84:327:20
3114.84:317:21

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.7 kWh/m².

For context, solar energy here swings from a low near 1.66 kWh/m² to a high of 6.32 kWh/m² in June across the year — May's 5.7 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.3Bright
25.3Bright
35.4Bright
45.4Bright
55.4Bright
65.4Bright
75.5Bright
85.5Bright
95.5Bright
105.5Bright
115.6Bright
125.6Bright
135.6Bright
145.7Bright
155.7Bright
165.7Bright
175.8Bright
185.8Bright
195.8Bright
205.8Bright
215.8Bright
225.9Bright
235.9Bright
245.9Bright
255.9Bright
265.9Bright
275.9Bright
285.9Bright
296.0Bright
306.0Bright
316.0Bright
Planning a trip in May

Is May a good time to visit Freeport?

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

5.9
Sightseeing
5th-best month of the year
3.4
Beach & pool
5th-best month of the year

May is a reasonable time to visit Freeport for sightseeing.

What to pack for Freeport in May

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

In May, Freeport sees daytime highs around 69°F and nights near 50°F. Worth packing: rain gear and sun protection. About 13 days see rain.

rain gearsun protection

UV index in Freeport 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 Freeport peaks around June 19 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 19UV 9Dec 22UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May8Very high
Jun9Very high
Jul8Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec2Low

Air quality in Freeport 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 Freeport is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (October, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateModerateGoodJul 1915 µg/m³Oct 238 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb13Moderate
Mar13Moderate
Apr12Good
May13Moderate
Jun14Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov8Good
Dec9Good
Location & terrain

Where is Freeport?

Freeport sits at 42.3°N, 89.6°W, 778 ft above sea level, in United States. The nearest listed city is Rockford, 27 mi away.

Topography around Freeport

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

Within 2 miles, the terrain around Freeport has only modest variations in elevation — a maximum elevation change of 177 ft around an average of 797 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 472 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 853 ft.

The land around Freeport is covered by trees (33%), grassland (24%) and cropland (21%) within 2 miles, cropland (75%) within 10 miles, and cropland (67%) within 50 miles.

2 miles
177 ft
10 miles
472 ft
50 miles
853 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
May weather nearby: Rockford 27 mi · Loves Park 29 mi · Machesney Park 30 mi · Dixon 32 mi · Beloit 34 mi · Sterling 35 mi · Belvidere 40 mi · Janesville 40 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 Freeport (42.2967°, -89.6212°, elevation 778 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).