Deerfield (IL) Temperature by Month
Deerfield, Illinois, United States of America has an average annual maximum temperature of 15°C (59°F), ranging from 0°C (32°F) in January to 29°C (84°F) in July. Below you'll find a full monthly breakdown and a comparison with cities worldwide.
Deerfield Monthly Temperatures
In Deerfield, temperatures can shift dramatically between warm in summer and very cold in winter. Nights follow the same pattern, with lows ranging 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 Deerfield by month:
The coolest part of the day is typically between 4 AM and 6 AM, while 3 PM is usually the warmest, when solar heating is at its peak. July, the city's warmest month, averages 319 hours of sunshine.
The chart below shows the average temperature throughout the year:
Temperature: Deerfield 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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Deerfield vs World: Temperature Compared
Deerfield'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:
Seville, Spain averages 23°C (73°F) a year — one of the warmer cities in Western Europe, with long hot summers.
Glasgow, Scotland averages 13°C (55°F) a year — mild but often grey, with cold winters and rarely hot summers.
Beijing, China averages 20°C (68°F) annually, but with big seasonal swings — very cold winters and hot summers.
Perth, Australia averages 25°C (77°F) annually, with a classic Mediterranean climate — hot dry summers and mild wet winters.
What Does the Temperature Feel Like in Deerfield?
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 Deerfield, 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 Deerfield this rarely lasts long on the ground.
For more on Deerfield's weather — including monthly rainfall, sunshine hours, and humidity — visit our Deerfield climate page.
