Question 1

What is the sunniest time of year in Chicago?

Accepted Answer

The sunniest time of year in Chicago is the summer, with August 2025 standing out as the brightest month of all. Chicago recorded 371.7 hours of sunshine in August 2025 — roughly 12.0 hours of sun per day.

Summer (June to August 2025) clearly dominated for sunshine in Chicago, delivering 1,024.9 hours in total and averaging about 341.6 hours per month. July followed August closely with 337.4 hours (around 10.9 hours daily), and June added 315.8 hours. Early autumn stayed bright too, as September 2025 still logged 300.7 hours of sunshine. Across the full year, Chicago accumulated 2,704.9 hours of sunshine in 2025.

By contrast, the darkest stretch came in midwinter: December 2025 saw just 91.3 hours of sunshine, with February close behind at 120.2 hours. That means a typical August day in Chicago offered roughly four times more sunshine than a December one.

For planning purposes, the long, bright days of June through August make this the ideal window for lakefront visits, outdoor dining, and festivals in Chicago, with August also being comfortably warm at a mean temperature of 22.6°C (72.7°F). If you want sunshine without peak crowds, September remains an excellent and still-sunny choice.

Question 2

What were the temperature extremes in Chicago in 2025?

Accepted Answer

In 2025, Chicago swung between a peak of 37.0°C (98.6°F) and a low of -21.8°C (-7.2°F), an annual temperature range of 58.8°C (about 106°F) that highlights the city's famously dramatic climate.

The hottest day in Chicago came on July 23, 2025, when the temperature topped out at 37.0°C (98.6°F). The coldest reading arrived during the depths of winter on February 18, 2025, with the thermometer plunging to -21.8°C (-7.2°F). Across the full year, the city averaged a mild 10.6°C (51.1°F), reflecting how those extremes balance out over the seasons.

Both ends of the spectrum were more than one-off spikes. Chicago recorded 33 days that reached at least 32.2°C (90°F) in 2025, concentrated in the summer months. On the cold side, the city saw 31 days where the low dropped to -10°C (14°F) or below, alongside 51 "ice days" when the temperature never climbed above freezing.

For residents and visitors, this means packing for genuine extremes. Summer in Chicago calls for heat-ready clothing and hydration during prolonged hot spells, while winter demands serious cold-weather gear, as sub-zero Fahrenheit conditions are a real possibility. The wide 2025 temperature range is a reminder that comfortable spring and autumn windows are often the most reliable times for outdoor plans in Chicago.

Question 3

Which season is the wettest in Chicago?

Accepted Answer

Summer is the wettest season in Chicago, with the city recording 528.8 mm (20.8 inches) of precipitation during summer 2025 (June to August) — far more than any other time of year.

Across the meteorological seasons in 2025, Chicago's rainfall broke down as follows:

- **Summer (June–August):** 528.8 mm (20.8 in)
- **Spring (March–May):** 324.5 mm (12.8 in)
- **Autumn (September–November):** 237.6 mm (9.4 in)
- **Winter (January–February):** 83.3 mm (3.3 in)

Summer alone delivered about 42% of Chicago's annual total of 1,245 mm (49.0 in) in 2025. The single wettest month was July with 189.9 mm (7.5 in), closely followed by August at 188.7 mm (7.4 in). At the other extreme, February was the driest month of the year with just 30.6 mm (1.2 in).

The pattern reflects Chicago's continental climate, where warm, humid summer air fuels frequent thunderstorms and heavy downpours, while cold winter months bring far less liquid precipitation. For visitors and residents, this means summer trips to Chicago should account for sudden afternoon storms, whereas spring and autumn generally offer drier, more settled conditions for outdoor plans.

Question 4

How windy is Chicago, and which months are the windiest in 2025?

Accepted Answer

Despite its "Windy City" nickname, Chicago saw moderate average wind speeds of 14.0 km/h (8.7 mph) across 2025, with spring and the cold-weather months being the breeziest periods.

In 2025, the windiest month in Chicago was April, averaging 15.8 km/h (9.8 mph), closely followed by January at 15.4 km/h (9.6 mph) and both March and December at 15.2 km/h (9.4 mph). Winds were calmest in late summer and early autumn, bottoming out in September at just 11.2 km/h (7.0 mph), with July (11.4 km/h / 7.1 mph) and August (12.1 km/h / 7.5 mph) close behind.

Grouped by meteorological season, spring (March–May) was the breeziest in Chicago at 15.1 km/h (9.4 mph), while summer (June–August) was the calmest at 12.6 km/h (7.8 mph). Overall, monthly averages stayed within a narrow band of 11.2 to 15.8 km/h (7.0 to 9.8 mph) throughout the year.

For visitors and residents, this means Chicago's breezes are most noticeable in spring and winter, when gusts off Lake Michigan add a sharp chill to already cold air. If you prefer calmer conditions for lakefront walks or cycling, the late-summer stretch from July through September offers Chicago's gentlest winds.

Question 5

What is the weather like in Chicago in December?

Accepted Answer

December in Chicago is cold, damp, and firmly wintry, with a 2025 monthly average temperature of -2.3°C (27.8°F). Days are short and chilly, and the city swings between hard freezes and brief mild spells.

Across December 2025, average daily highs reached just 1.6°C (34.9°F) while average lows dropped to -6.9°C (19.7°F). On 15 of the month's 31 days the temperature never climbed above freezing, and 26 days saw sub-zero (below 0°C / 32°F) overnight lows. The coldest moment came on December 14, when the thermometer fell to -18.5°C (-1.3°F).

December weather in Chicago is changeable, too. A late-month thaw pushed the high to 14.5°C (58.1°F) on December 28 before temperatures crashed again. The month recorded 67.7mm (2.67 inches) of precipitation across 12 days with measurable amounts, and humidity averaged a damp 79.7%.

For visitors, this means Chicago in December calls for serious winter gear: an insulated coat, hat, and gloves are essential, especially given the wind chill near Lake Michigan. With so many days below freezing, sidewalks and roads can be icy, so plan extra travel time. The upside is a true seasonal atmosphere — holiday markets, ice skating, and festive lights all thrive in this cold, classic Chicago December.

Chicago

Illinois

FAQ

What is the sunniest time of year in Chicago?

What were the temperature extremes in Chicago in 2025?

Which season is the wettest in Chicago?

How windy is Chicago, and which months are the windiest in 2025?

What is the weather like in Chicago in December?