Winthrop Harbor, IL climate
Winthrop Harbor has chilly, snowy winters and pleasant summers. A typical July afternoon reaches 81°, a January night drops to 17°, and about 36 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Winthrop Harbor feels like
Winter
Spring
Summer
Fall
Winthrop Harbor weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 31° | 17° | 1.8" | 11.3" | 10 | 18 | 15° – 35° |
| February | 35° | 20° | 1.7" | 9.8" | 9 | 12 | 15° – 37° |
| March | 44° | 29° | 2.3" | 5.7" | 10 | 5 | 29° – 50° |
| April | 54° | 38° | 3.8" | 0.8" | 12 | 0 | 38° – 52° |
| May | 65° | 47° | 4.0" | 0 | 12 | 0 | 51° – 62° |
| June | 75° | 57° | 4.2" | 0 | 11 | 0 | 62° – 71° |
| July | 81° | 64° | 3.3" | 0 | 9 | 0 | 68° – 79° |
| August | 80° | 64° | 3.6" | 0 | 10 | 0 | 66° – 77° |
| September | 73° | 56° | 3.4" | 0 | 9 | 0 | 59° – 69° |
| October | 61° | 44° | 3.3" | 0.1" | 10 | 0 | 49° – 58° |
| November | 48° | 33° | 2.4" | 1.5" | 10 | 1 | 32° – 49° |
| December | 36° | 23° | 1.9" | 7.0" | 10 | 7 | 18° – 39° |
| Year | 57° | 41° | 35.5" | 36.2" | 120 | 44 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Winthrop Harbor
Winthrop Harbor gets 36 inches of rain and melted snow a year. June is the wettest month and February the driest. Rain or snow falls on about 120 days a year. Snow covers the ground about 44 days of the year.
About 189 frost-free days a year
In half of years the last 32° night comes by April 19 and the first one by October 26. That leaves about 189 frost-free days for gardens, longer than 63% of U.S. towns.
Heating and cooling a home in Winthrop Harbor
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Winthrop Harbor, 92% of that work is heating and 8% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Winthrop Harbor and its neighbors
Winthrop Harbor borders 4 towns with climate data. January nights across them vary by 1.6°. Pleasant Prairie has both the coldest January nights (16°) and the hottest July afternoons (82°). Winthrop Harbor’s January low is 17° and its July high 81°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Winthrop Harbor compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Winthrop Harbor averaged 0.9° warmer than the 1900s. The biggest change is in December (+2.4°). The shift is smaller than in 74% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Winthrop Harbor’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 15° to 37°. June is the most reliable, staying within 9°.
Common questions about Winthrop Harbor’s climate
What is the coldest month in Winthrop Harbor?
January, with a typical high of 31° and a low of 17°.
What is the hottest month in Winthrop Harbor?
July, with a typical high of 81° and a low of 64°. About 7 days a year reach 90°.
How much snow does Winthrop Harbor get?
About 36 inches in a normal winter, most of it in January.
When is the first frost in Winthrop Harbor?
In half of years the first 32° night comes by October 26, and the last spring frost by April 19.
What is the rainiest month in Winthrop Harbor?
June, with 4.2 inches of rain and melted snow. The year totals 36 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Winthrop Harbor itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Kenosha, WI (6 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.