Yosemite National Park is definitely worth a visit
Vast forests, blue lakes, towering sequoias, and majestic waterfalls hint at the beauty of Yosemite National Park—a true natural masterpiece.
Illinois Weather by Month: Temperature & Rainfall Guide
Illinois is a region in the United States of America. Many people wonder what the weather conditions are in Illinois over the year. What is the best time to visit Illinois?
This page shows the average weather conditions by month in Illinois over the year in: January, February, March, April, May, June, July, August, September, October, November, December.
Illinois in January
In January the weather in Illinois is generally less favorable. January is a winter month. The temperatures range from very low in Galena with -2°C (28°F) to low in Metropolis with 6°C (43°F). On average, this month is one of the coldest months of the year in Illinois. So be prepared and make sure to dress up warm.
Find more detailed climate information for Illinois in January here.
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Illinois in February
In February the weather in Illinois is generally less favorable. February is a winter month. The temperatures range from very low in Galena with -2°C (28°F) to low in Metropolis with 7°C (45°F). It is a very cold month in some areas, so be prepared and make sure to dress up warm.
Find more detailed climate information for Illinois in February here.
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Illinois in March
In March the weather in Illinois is generally less favorable. The temperatures range from low in Roscoe with 5°C (41°F) to moderate in Metropolis with 15°C (59°F).
Find more detailed climate information for Illinois in March here.
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Illinois in April
In April the weather in Illinois ranges from less favorable in Waukegan to good in Joliet. The temperatures range from low in Zion with 12°C (54°F) to pleasant in Metropolis with 21°C (70°F).
Find more detailed climate information for Illinois in April here.
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Illinois in May
In May the weather in Illinois ranges from very good in Chicago to excellent in Freeport. The temperatures range from pleasant in Zion with 18°C (64°F) to high in Metropolis with 25°C (77°F).
Find more detailed climate information for Illinois in May here.
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Illinois in June
In June the weather in Illinois is generally very good. June is a summer month. The temperatures range from high in Roscoe with 23°C (73°F) to very high in Metropolis with 31°C (88°F).
Find more detailed climate information for Illinois in June here.
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Illinois in July
In July the weather in Illinois ranges from very good in Chicago to excellent in Waukegan. July is a summer month. The temperatures range from high in Roscoe with 26°C (79°F) to very high in O'Fallon with 31°C (88°F). On average, this month is one of the warmest months of the year in Illinois. So be prepared and make sure to dress lightly.
Find more detailed climate information for Illinois in July here.
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Illinois in August
In August the weather in Illinois ranges from very good in Chicago to excellent in Waukegan. August is a summer month. The temperatures range from high in Roscoe with 24°C (75°F) to very high in Metropolis with 31°C (88°F).
Find more detailed climate information for Illinois in August here.
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Illinois in September
In September the weather in Illinois ranges from very good in Schaumburg to excellent in Chicago. The temperatures range from pleasant in Roscoe with 21°C (70°F) to high in Metropolis with 28°C (82°F).
Find more detailed climate information for Illinois in September here.
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Illinois in October
In October the weather in Illinois ranges from good in Chicago to very good in Peru. The temperatures range from moderate in Roscoe with 14°C (57°F) to pleasant in Metropolis with 21°C (70°F).
Find more detailed climate information for Illinois in October here.
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Illinois in November
In November the weather in Illinois is generally less favorable. The temperatures range from low in Roscoe with 8°C (46°F) to moderate in Metropolis with 14°C (57°F).
Find more detailed climate information for Illinois in November here.
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Illinois in December
In December the weather in Illinois is generally less favorable. December is a winter month. The temperatures range from very low in Galena with 1°C (34°F) to low in Metropolis with 9°C (48°F). It is a very cold month in some areas, so be prepared and make sure to dress up warm.
Find more detailed climate information for Illinois in December here.
perfect weather
pleasant
tolerable
unpleasant
poor
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Top destinations
More climate information for the top 5 destinations in Illinois:
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Yosemite National Park is definitely worth a visit
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