Photo: bogdanstepniak · CC BY 3.0January in Carol Stream bites harder than in 84% of U.S. towns
Peak summer warmth arrives in July, with afternoons near 84°. By precipitation alone, it ranks drier than 67% of U.S. towns. Since 1901–2000, the year has warmed by 1.3°, most of all in December. Plan time outside from May to October, when highs sit at 62–84°.
A year in Carol Stream at a glance
Each month’s typical high and low, and what it brings.
What stands out about Carol Stream’s climate
Compared with towns across the U.S., with Carol Stream’s place in Illinois beside it.
What a year in Carol Stream feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 174 frost-free days a year
In half of years the last 32° night comes by April 25 and the first by October 19. Frost and day counts come from NOAA’s station at West Chicago Dupage Airport, 6 miles from the town’s center, at about the same height.
The 2023 USDA map puts Carol Stream’s center in zone 5b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −10°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 46 inches of snow a winter
Snow, measured at St. Charles 0.1 E, IL, falls mostly in February. Precipitation (rain plus melted snow) adds up to 38 inches a year; May is the wettest month and February the driest. Rain or snow falls on about 129 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Carol Stream
89% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at West Chicago Dupage Airport.
Living with Carol Stream’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
174 frost-free days in zone 5b. The last frost comes by Apr 25 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 19.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August, September and October. 6.1 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Carol Stream from natural hazards, river flooding is the largest share (50%); heat waves, cold waves, winter storms and ice storms together are 24%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Carol Stream and its neighbors
Every town next door is within a degree of Carol Stream in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Carol Stream’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Carol Stream, IL | 15° | 84° | 38" | 46" |
| Coldwater, MI | 17° | 83° | 39" | 43" |
| Southport, NY | 16° | 83° | 36" | 42" |
| Old Forge, PA | 18° | 84° | 40" | 45" |
| Shelby, OH | 18° | 83° | 40" | 49" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Carol Stream averaged 1.3° warmer than the 1900s. The biggest change is in December (+2.6°).
A smaller shift than in 53% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Carol Stream compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Carol Stream’s place among Illinois’.
Carol Stream weather by month
Highs, lows and precipitation from NOAA’s grid at Carol Stream’s center; snow, wet days and snow on the ground from St. Charles 0.1 E, IL. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 30° | 15° | 1.8" | 11.2" | 11 | 14° – 34° |
| February | 35° | 19° | 1.8" | 13.0" | 10 | 14° – 38° |
| March | 46° | 28° | 2.3" | 5.0" | 11 | 29° – 52° |
| April | 59° | 37° | 3.8" | 2.9" | 12 | 40° – 55° |
| May | 71° | 48° | 4.8" | 0.0" | 13 | 53° – 66° |
| June | 80° | 58° | 4.5" | 0.0" | 12 | 65° – 74° |
| July | 84° | 63° | 3.8" | 0.0" | 10 | 68° – 80° |
| August | 82° | 62° | 3.9" | 0.0" | 9 | 66° – 78° |
| September | 75° | 54° | 3.4" | 0.0" | 9 | 59° – 69° |
| October | 62° | 42° | 3.4" | 0.2" | 11 | 48° – 58° |
| November | 48° | 31° | 2.5" | 3.7" | 9 | 32° – 48° |
| December | 36° | 21° | 2.1" | 10.2" | 12 | 15° – 38° |
| Year | 59° | 40° | 38.1" | 46.2" | 129 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 14° to 38°. June is the most reliable, staying within 9°.
Where Carol Stream’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Carol Stream’s center.
- Snow: St. Charles 0.1 E, IL.
- Frost, freezing nights, 90° and 100° days, heating and cooling: West Chicago Dupage Airport, 6 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Carol Stream’s climate
What is the weather like in Carol Stream?
A typical July afternoon reaches 84°, a January night drops to 15°, and about 46 inches of snow falls in a normal winter. Colder January nights than 84% of U.S. towns; cooler July afternoons than 62% of U.S. towns.
How cold does it get in Carol Stream in winter?
January nights average 15°. About 134 nights a year reach 32° or below and 9 reach 0° or below. In the coldest January of the last 30 years the month averaged 14°.
How much snow does Carol Stream get?
About 46 inches in a normal winter at St. Charles 0.1 E, IL, most of it in February.
How hot does it get in Carol Stream?
July, with a typical high of 84° and a low of 63°. About 15 days a year reach 90° (West Chicago Dupage Airport).
When is the first and last frost in Carol Stream?
In half of years the last spring frost (32°) comes by April 25 and the first fall frost by October 19, about 174 frost-free days, at West Chicago Dupage Airport.
What growing zone is Carol Stream in?
Zone 5b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −10°.
What is the best time of year to visit Carol Stream?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Carol Stream getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 53% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Carol Stream.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.