Downers Grove (IL) Temperature by Month
The average annual maximum temperature in Downers Grove, Illinois, United States of America is 15°C (59°F), with daytime highs ranging from 0°C (32°F) in January to 29°C (84°F) in July. This page covers monthly averages, day-night differences, and how Downers Grove compares to cities worldwide.
Downers Grove Monthly Temperatures
The climate in Downers Grove is dynamic, ranging widely from very cold in winter to comfortable in summer. Nights are significantly colder, with lows dropping from 18°C (64°F) in July to -9°C (16°F) in January.
The chart below illustrates the average maximum day and minimum night temperatures in Downers Grove by month:
From around 4 AM to 6 AM temperatures are at their lowest; by 3 PM they've climbed to their daily peak. July, the warmest month, averages 319 hours of sunshine.
The chart below shows the average temperature throughout the year:
Temperature: Downers Grove vs the United States of America
The map below shows the annual temperature across the United States of America. You can also select individual months if you want to compare a specific time of year.
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Downers Grove vs World: Temperature Compared
Downers Grove's average annual maximum temperature is 15°C (59°F). To put that in context, here's how it compares to a few well-known destinations:
Barcelona, Spain has an annual average of around 21°C (70°F), with warm summers and mild, fairly short winters.
On the cooler end, Oslo, Norway averages just 10°C (50°F) annually, with pleasant summers but long, cold winters.
Buenos Aires, Argentina averages 23°C (73°F) a year, with hot summers and mild winters — and seasons reversed compared to Europe.
Brisbane, Australia averages 26°C (79°F) a year, with warm winters and hot, humid summers.
What Does the Temperature Feel Like in Downers Grove?
Temperature alone doesn't tell the whole story — humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.
In the cooler months, when temperatures drop below 10°C, high humidity makes the cold feel more cutting than it would in dry conditions.
In Downers Grove, January is the coolest month, with average highs of 0°C (32°F) and humidity around 72% — considered high. In July, the warmest month, temperatures average 29°C (84°F) with 68% humidity — conditions that feel high. For a full picture, see our humidity page.
Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.
The readings come from a range of sources — land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.
Seasonal temperature shifts influence more than just how warm it feels — they also drive changes in rainfall, cloud cover, and wind patterns throughout the year.
Warmer air holds more moisture, which tends to mean heavier or more frequent rain during the warmer months. When temperatures drop in winter, any precipitation that does fall is more likely to come as snow or sleet, though in Downers Grove this rarely lasts long on the ground.
For more on Downers Grove's weather — including monthly rainfall, sunshine hours, and humidity — visit our Downers Grove climate page.
