Climate and average weather in Belvidere

In Belvidere, the summers are warm, showery, and partly cloudy and the winters are very cold, snowy, and mostly cloudy.

Best: mid May to mid October

Over the course of the year, the temperature in Belvidere typically varies from 15°F to 82°F, and is rarely below -5°F or above 90°F. July is the hottest month of the year, while January is the coldest.

Based on the travel score, the best time of year to visit Belvidere for warm-weather activities is from mid May to mid October.

Hottest
Jul
82°
Coldest
Jan
15°
Wettest
May
4.4 in
Driest
Feb
1.8 in
Rain / yr
36.3 in
114 wet days
Daylight
8.9–15.1 h
shortest–longest
Elevation
781 ft
42.3°N
Clearest
Sep
50% cloud

Belvidere is city in Illinois, United States.

Density
788/km²
people per km²
Founded
1835

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

Belvidere weather by month, at a glance

The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.

Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around mid May to mid October.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in Belvidere, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.

The hot season lasts 4.4 months, from May 16 to September 27, with daily high temperatures above 68°F. The hottest month of the year in Belvidere is July, with an average high of 82°F and low of 64°F.

The cool season lasts 3.0 months, from December 2 to March 2, with daily high temperatures below 39°F. The coldest month of the year in Belvidere is January, with an average low of 15°F and high of 29°F.

Days typically run about 17°F warmer than nights, with the widest day–night swing (around 19°F) in September.

20°40°60°80°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°F)Avg low (°F)
Jan2915
Feb3319
Mar4529
Apr5839
May6950
Jun7860
Jul8264
Aug8062
Sep7354
Oct6042
Nov4631
Dec3421

How hot and cold Belvidere really feels

Feels-like highFeels-like lowactual air temp

The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.

On the coldest nights, wind chill pulls the feels-like down to about 2°F (around January 21), with roughly 167 freezing days a year (feels-like at or below 32°F) 87 of them bitterly cold — worst in January.

20°40°60°80°JanFebMarAprMayJunJulAugSepOctNovDec
Feels-like high (°F)Air high (°F)Feels-like low (°F)Air low (°F)
Jan2929415
Feb3333819
Mar45452029
Apr58583339
May68694850
Jun78786060
Jul82826464
Aug80806262
Sep73735454
Oct60603742
Nov46462331
Dec34341121

Average hourly temperature in Belvidere

A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on July afternoons, near 82°F, and coldest before dawn in January, near 15°F.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM

Belvidere weather by month

Every month at a glance. Click a month for its detailed page.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan29° / 15°1.97.75.89.30.0
Feb33° / 19°1.87.25.110.30.0
Mar45° / 29°2.59.43.311.61.2
Apr58° / 39°4.212113.13.9
May69° / 50°4.412.5014.45.9
Jun78° / 60°3.911.70156.4
Jul82° / 64°3.410.2014.86.4
Aug80° / 62°3.49.7013.76.7
Sep73° / 54°3.28.6012.37.0
Oct60° / 42°3.08.80.110.85.0
Nov46° / 31°2.47.91.89.61.3
Dec34° / 21°2.17.84.890.0

Chance of rain

How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.

Belvidere gets about 36.3 in of precipitation a year. On a typical day the chance of rain is often wet, but that rises and falls sharply with the seasons.

The wetter season lasts 4.9 months, from around Mar 24 to Aug 18, peaking in April at about 41% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Feb 3.

May is the wettest month by volume, with 4.4 in over about 13 wet days; February is the driest, with 1.8 in. Some of the cold-season precipitation falls as snow.

0%10%20%30%40%50%JanFebMarAprMayJunJulAugSepOctNovDecdrierwetterdriermostly drysome rainoften wetvery wetApr 21 · 41%Feb 3 · 23%
Rain on a day (%)Rain days
Jan258
Feb267
Mar309
Apr4012
May4113
Jun3912
Jul3310
Aug3110
Sep299
Oct289
Nov278
Dec258

Monthly rainfall

Over a full year, Belvidere collects about 36.3 in of rain across 114 wet days — roughly 3.0 in in an average month.

It doesn’t fall evenly. May is the wettest month with 4.4 in, while February is the driest at just 1.8 in. The three wettest months alone bring about 35% of the year’s total, and some of the cold-season precipitation falls as snow.

0123456JanFebMarAprMayJunJulAugSepOctNovDec1.91.82.54.24.43.93.43.43.23.02.42.1
Rainfall (in)Rain daysSnow days
Jan1.986
Feb1.875
Mar2.593
Apr4.2121
May4.4130
Jun3.9120
Jul3.4100
Aug3.4100
Sep3.290
Oct3.090
Nov2.482
Dec2.185

Snow in Belvidere

Average snowy days through the year, the snow-season span, and estimated snowfall — for ski trips and the perennial 'will there be snow at Christmas?' question.

Belvidere averages about 22 snowy days a year. Snow season runs roughly Oct 29 to Apr 25 — about 5.9 months.

January is snowiest, with roughly 6 days of snow and an estimated 11 in of snowfall. Over the year that adds up to an estimated 40 in of snow.

02468JanFebMarAprMayJunJulAugSepOctNovDecsnow seasonsnow seasonJan 24
Snow daysSnowfall (in)
Jan611
Feb59
Mar35
Apr13
May00
Jun00
Jul00
Aug00
Sep00
Oct00
Nov23
Dec58

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

How often the daytime sky is clear, partly cloudy or overcast.

In Belvidere, the average share of the sky covered by clouds shows moderate seasonal variation over the course of the year.

The clearer part of the year begins around May 28 and lasts for 4.8 months, ending around October 21. The clearest month is September, when the sky is clear, mostly clear, or partly cloudy 57% of the time on average.

The cloudier part of the year begins around October 22 and lasts for 7.2 months, ending around May 27. The cloudiest month is January, when it is overcast or mostly cloudy 68% of the time.

0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JanFebMarAprMayJunJulAugSepOctNovDecSep 7 · 60%Jan 30 · 31%clearmostly clearpartly cloudymostly cloudyovercastcloudierclearercloudier
Clearer (%)Cloudier (%)
Jan3268
Feb3466
Mar3862
Apr3565
May4060
Jun4852
Jul5446
Aug5545
Sep5743
Oct4654
Nov3763
Dec3466

Daylight, sunrise and sunset

DaylightNight

Hours of daylight through the year, with sunrise and sunset times.

The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around June 14, brings about 15 h 06 min of light; the shortest, around December 13, only 8 h 54 min — a swing of roughly 6 h 12 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan9.37:284:42
Feb10.37:015:19
Mar11.66:165:54
Apr13.15:216:30
May14.44:407:03
Jun15.04:237:28
Jul14.84:377:25
Aug13.75:086:51
Sep12.35:415:58
Oct10.86:155:05
Nov9.66:544:27
Dec9.07:244:19

Sunny days

How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.

Belvidere averages about 9 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 6 and 13 days.

The sunnier stretch runs 4.7 months, from around Jun 3 to Oct 23. The sunniest month is September, with roughly 13 sunny days (mixed).

The greyest month is April, down near 7 sunny days — about 47% fewer than the September peak.

05101520JanFebMarAprMayJunJulAugSepOctNovDecgreyersunniergreyergloomymixedbrightSep 1013 daysApr 26 days
Sunny daysSky
Jan7Gloomy
Feb7Gloomy
Mar7Gloomy
Apr7Gloomy
May8Gloomy
Jun9Mixed
Jul10Mixed
Aug11Mixed
Sep13Mixed
Oct10Mixed
Nov8Gloomy
Dec7Gloomy

Humidity comfort

DryComfortableHumidMuggyOppressiveMiserable

Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.

Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.

In Belvidere, how humid it feels changes dramatically over the year.

The more humid part of the year lasts 4.0 months, from around May 24 to September 21. The muggiest month is July, when the air feels humid, muggy or worse about 64% of the time.

The most comfortable stretch runs from around September 22 to May 23, and March is the most comfortable month — the air is dry or comfortable 100% of the time.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecMar 8 · 100%Jul 18 · 33%oppressivemuggydryhumidcomfortablecomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
Jan10000000
Feb10000000
Mar9910000
Apr9631000
May75138400
Jun3423192030
Jul15212526121
Aug1825242390
Sep5321141020
Oct9063100
Nov9910000
Dec10000000

Wind

Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.

This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.

Across the year, average wind speed in Belvidere is typically light breeze, near 8 mph, and varies moderately with the seasons.

The windier part of the year lasts 7.6 months, from around Oct 1 to May 20. The windiest month is April, averaging about 9 mph (light breeze).

The calmer part of the year runs from around May 21 to Sep 30, with August the calmest month at about 6 mph.

051015JanFebMarAprMayJunJulAugSepOctNovDecwindiercalmerwindiercalmlight breezebreezyApr 13 · 9 mphAug 7 · 6 mph
Wind speed (mph)Feels
Jan9light breeze
Feb9light breeze
Mar9light breeze
Apr9light breeze
May8light breeze
Jun7calm
Jul7calm
Aug6calm
Sep7calm
Oct9light breeze
Nov9light breeze
Dec9light breeze

Best time to visit Belvidere

TravelBeach/poolTemperatureCloudsPrecipitation

To characterize how pleasant the weather is in Belvidere throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.

Around late May, Belvidere is still near the start of its best-weather window — great conditions with the peak-season crowds not yet at full swing.

Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.

The travel score favors clear, rainless days with daytime highs between 64°F and 82°F. Based on this score, the best time of year to visit Belvidere for general outdoor tourist activities is from mid May to mid October, with a peak score in the first week of September.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timetravel scoretemperaturecloudsprecipitationSep 7 · 7.3

The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Travel score (0–10)Rating
Jan0.0poor
Feb0.0poor
Mar1.2poor
Apr3.9fair
May5.9good
Jun6.4good
Jul6.4good
Aug6.7good
Sep7.0good
Oct5.0fair
Nov1.4poor
Dec0.0poor

The beach/pool score favors clear, rainless days with daytime highs between 75°F and 93°F. Based on this score, the best time of year to visit Belvidere for hot-weather activities is from early June to mid September, with a peak score in the second week of July.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebeach/pool scoretemperaturecloudsprecipitationJul 12 · 6.8

The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

What to pack for Belvidere, by month

EssentialRecommendedOptional

Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.

For a warm-season trip around July (highs near 82°F), the essentials are light clothes, rain gear and sun protection. In the cold season around January (highs near 29°F), pack a warm layer and a heavy coat.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In July, Belvidere sees daytime highs around 82°F and nights near 64°F. Pack light clothes and sun protection. Worth having: rain gear. About 10 days see rain.

UV index (midday) in Belvidere by month

LowModerateHighVery highExtreme

Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.

Under clear skies, the midday UV index in Belvidere peaks around June 19 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 at about 1 (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 20UV 1
UV index (midday)Level
Jan2Low
Feb2Moderate
Mar4Moderate
Apr6High
May8Very high
Jun9Very high
Jul8Very high
Aug8Very high
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Average hourly UV index in Belvidere

LowModerateHighVery highExtreme

Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.

The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

UV falls off far faster than brightness as the sun drops, so even in June the burn window is concentrated in the middle of the day: about 8.5 hours a day reach index 3 (protection recommended), and 5 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM
UV ≥ 3 (h/day)UV ≥ 6 (h/day)
Jan00
Feb00
Mar40
Apr60
May7.54
Jun8.55
Jul85
Aug7.54
Sep60
Oct20
Nov00
Dec00

Air quality in Belvidere by month

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly average.

Air quality in Belvidere is worst in July — around 17 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (October, 9 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodJul 1817 µg/m³Oct 229 µg/m³
PM2.5 (µg/m³)Level
Jan12Moderate
Feb15Moderate
Mar16Moderate
Apr14Moderate
May15Moderate
Jun16Moderate
Jul17Moderate
Aug16Moderate
Sep13Moderate
Oct9Good
Nov10Good
Dec11Good
Almanac & agriculture

Growing season

Chance of a frost-free dayTypical season (≥50%)

The growing season in Belvidere typically lasts about 234 days, from around March 25 to November 13 — the span where a frost-free day is more likely than not. It is reliably frost-free from April 24 to October 14.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecgrowing seasonJan 2710%Mar 2550%Apr 2490%Oct 1490%Nov 1350%Jan 1510%
Frost-free chance (%)Frost nights
Jan1131
Feb1428
Mar3931
Apr8021
May980
Jun1000
Jul1000
Aug1000
Sep990
Oct8816
Nov4830
Dec1931

Growing degree days

Degree days (base 50°F)Frost-free shaded

Growing degree days tally heat above 50°F: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Belvidere banks about 2,709 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around July.

01,0002,0003,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°F·days)
Jan0
Feb0
Mar0
Apr17
May284
Jun571
Jul709
Aug646
Sep409
Oct74
Nov0
Dec0

Solar energy

Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.

Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.

Belvidere receives about 4.0 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 1.6 and 6.4 kWh/m².

The brighter stretch of the year lasts 6.3 months, from around Mar 16 to Sep 23. The brightest month is June, averaging about 6.3 kWh/m² (intense).

The dimmest month is December, down near 1.7 kWh/m² — roughly 73% less than the June peak.

012345678JanFebMarAprMayJunJulAugSepOctNovDecdimmerbrighterdimmerdimmoderatebrightintenseJun 286.4 kWhDec 211.6 kWh
Solar energy (kWh/m²)Level
Jan2.0Dim
Feb3.0Moderate
Mar4.0Bright
Apr4.9Bright
May5.7Bright
Jun6.3Intense
Jul6.2Intense
Aug5.4Bright
Sep4.4Bright
Oct3.0Moderate
Nov2.0Moderate
Dec1.6Dim

Where is Belvidere?

Belvidere sits at 42.3°N, 88.8°W, 781 ft above sea level, in United States. The nearest listed city is Machesney Park, 11 mi away.

Topography around Belvidere

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

Within 2 miles, the terrain around Belvidere has only modest variations in elevation — a maximum elevation change of 131 ft around an average of 784 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 325 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 679 ft.

The land around Belvidere is covered by cropland (27%), artificial surfaces (25%) and grassland (24%) within 2 miles, cropland (62%) within 10 miles, and cropland (60%) and trees (20%) within 50 miles.

2 miles
131 ft
10 miles
325 ft
50 miles
679 ft
treesgrasslandcroplandartificial surfaceswater
Nearby: Machesney Park 11 mi · Loves Park 12 mi · Rockford 13 mi · Beloit 19 mi · Woodstock 21 mi · Sycamore 21 mi · Huntley 22 mi · DeKalb 24 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 Belvidere (42.2639°, -88.8443°, elevation 781 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).