Prospect Heights (IL) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Prospect Heights.
Climate overview of Prospect Heights
Temperatures in Prospect Heights, Illinois, United States of America, vary greatly throughout the year. July is the hottest month at 29°C (84°F), while January is the coldest at -1°C (30°F).
With around 1030 mm (41 in) of annual rain/snowfall, Prospect Heights has a notably wet climate. However, this rain/snowfall is not evenly distributed, the city has warm summers and very cold winters. The wettest month is June. The sunniest month is July, with 10.6 hours of sunshine per day on average.
Prospect Heights Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Prospect Heights - and find the best time to visit.
Monthly Temperature in Prospect Heights
The climate in Prospect Heights is known for significant temperature differences throughout the year, making the weather dynamic. Average daytime temperatures reach a comfortable 29°C (84°F) in July. In January, the coolest month of the year, temperatures drop to a very cold -1°C (30°F).
At night, temperatures range from around 18°C (64°F) in July to -9°C (16°F) in January.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Prospect Heights
Prospect Heights has a notably wet climate with abundant precipitation, recording 1030 mm (41 in) of rain/snowfall per year. Prospect Heights can be quite wet during June, receiving approximately 121 mm (4.8 in) of precipitation over 14 rainy days.
In contrast, during the driest month (January), you will experience much drier conditions, with 46 mm (1.8 in) of precipitation spread across 10 snowy days. For more details, please visit our Prospect Heights Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in Prospect Heights
Prospect Heights can be enjoyed more throughout the sunniest month of July under a blue sky, with approximately 10.6 hours of sunshine daily. In contrast, the city experiences much darker days in December, with only 3.6 hours of sunlight per day.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Daily hours of sunshine
Daily percentage of sunshine
Humidity in Prospect Heights by Month
The relative humidity is high throughout the year in Prospect Heights.
The city experiences its highest humidity in December, reaching 76%. In May, the humidity drops to its lowest level at 64%. What does this mean? Read our detailed page on humidity levels for further details.
Relative humidity over the year
Wind Speed in Prospect Heights
The mean wind speed over the year ranges from 4 m/s (8 knots) in June, July, August and September to 6 m/s (12 knots) in January, March and April. What does this mean?
The mean monthly wind speed over the year (meters per second)
Best Time to Visit Prospect Heights
Monthly ratings reflect general weather comfort, based on daytime temperature and rainfall. Swimming and winter conditions are highlighted separately where relevant.
- Best overall: September
- Warmest weather: July and August
- Most sunshine: June and July
- Fewer rainy days: January, February, March, September and November
- Seasonal pattern: Warm summers and very cold winters
- Coldest conditions: January, with freezing nights around -9°C (16°F).
Frequently asked questions about the climate in Prospect Heights
What is the best time to visit Prospect Heights?
September typically offers the most optimal weather in Prospect Heights. In contrast, January, February, March, November and December tend to have less optimal conditions. Prospect Heights has warm summers and very cold winters.
What temperatures can I expect in Prospect Heights?
Daytime highs range from -1°C (30°F) in January to 29°C (84°F) in July. Nighttime lows range from -9°C (16°F) to 18°C (64°F). Temperatures vary considerably through the year.
How much rain does Prospect Heights get?
Annual rainfall is around 1030 mm (41 in). June is the wettest month with 121 mm (4.8 in), while January is the driest with 46 mm (1.8 in).
How sunny is Prospect Heights?
Prospect Heights receives around 2,509 hours of sunshine per year. July is the sunniest month with 319 hours, while December is the cloudiest with just 107 hours. Overall, Prospect Heights enjoys abundant sunshine.
Prospect Heights 3-Day Forecast
Prospect Heights on the map
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