Cook County Weather Forecast
Cook County weather: 69°F, clear. Hourly forecast, 14-day outlook, UV, air quality and the best time to visit.
Will it rain in Cook County?
Possibly - there is a 41% chance in Cook County today.
A 41% chance means rain is likely somewhere nearby at some point - carry a layer, but do not cancel.
Over the next 7 days, about 0,1 in of precipitation is forecast, with the wettest days falling on Fri.
The next 7 days look unusually dry - roughly 9% of a normal August week (0,1 in against 0,7 in).
16-day forecast for Cook County
Daily highs and lows, precipitation and UV.
| Day | Conditions | High / Low | Precip | Wind | UV |
|---|---|---|---|---|---|
| Fri, Aug 21 | ☁️ Overcast | 76° / 60° | 41% | 9 mph | 6 |
| Sat, Aug 22 | ☁️ Overcast | 81° / 65° | 15% | 13 mph | 7 |
| Sun, Aug 23 | ☁️ Overcast | 75° / 59° | 3% | 12 mph | 7 |
| Mon, Aug 24 | ☁️ Overcast | 73° / 60° | 0% | 10 mph | 6 |
| Tue, Aug 25 | ☁️ Overcast | 78° / 61° | 9% | 9 mph | 7 |
| Wed, Aug 26 | 🌦️ Light drizzle | 84° / 62° | 21% · 0,1 in | 14 mph | 7 |
| Thu, Aug 27 | ☀️ Clear sky | 80° / 66° | 17% | 10 mph | 7 |
| Fri, Aug 28 | ☁️ Overcast | 79° / 68° | 8% | 8 mph | 6 |
| Sat, Aug 29 | 🌦️ Drizzle | 87° / 66° | 15% · 0,0 in | 10 mph | 6 |
| Sun, Aug 30 | ⛈️ Violent showers | 82° / 70° | 22% · 2,1 in | 15 mph | 4 |
| Mon, Aug 31 | 🌦️ Light drizzle | 86° / 72° | 26% · 0,0 in | 14 mph | 6 |
| Tue, Sep 1 | 🌦️ Light drizzle | 88° / 72° | 24% · 0,0 in | 9 mph | 6 |
| Wed, Sep 2 | 🌧️ Showers | 89° / 70° | 16% · 0,5 in | 18 mph | 6 |
| Thu, Sep 3 | ☁️ Overcast | 84° / 71° | 29% | 15 mph | 3 |
| Fri, Sep 4 | 🌧️ Heavy drizzle | 72° / 67° | 16% · 0,2 in | 14 mph | 5 |
| Sat, Sep 5 | ☁️ Overcast | 70° / 61° | 16% | 15 mph | 6 |
What this means for Cook County
Today is slightly cooler than average for August. The forecast high of 76°F is 3.6°F below the 79°F typical for this month.
A 41% chance means rain is likely somewhere nearby at some point - carry a layer, but do not cancel.
No weather-related travel disruption is expected today. Roads and airports should run normally.
Northern Hemisphere, so peak summer falls in June to August.
The gap between the warmest and coldest month averages 84°F.
What to pack, what to skip
- Lightweight, light-coloured clothing and a refillable water bottle
- Sunglasses, a brimmed hat and SPF 30+
- If your dates are flexible, avoid January, February and December - historically the least comfortable months here.
See the Cook County forecast by time range
Cook County weather - more answers
Explore Cook County
Every topic we hold for this place, and the same topic for the places around it.
Weather for related places
Frequently asked questions
Where is Cook County?
Cook County is a county in Illinois. Its coordinates are 41.8781, -87.6298. It lies in North America.
What is the weather like in Cook County right now?
It is currently 69°F (20°C) with clear. Humidity is 81% and wind is 5 mph.
When is the best time to visit Cook County?
May, June, August, September and October offer the most comfortable conditions in Cook County, which has a continental climate. January, February and December are usually the hardest months for outdoor plans.
What time zone is Cook County in?
Cook County observes America/Chicago (UTC-05:00). The local time is 7:45 AM.
How many people live in Cook County?
Cook County has a population of approximately 5.1 million.
What is the nearest airport to Cook County?
The closest airports are O'Hare International Airport (ORD), 16 mi away.
What are the top things to do in Cook County?
Popular options include Indiana Dunes National Park, Starved Rock State Park and Lake Michigan.
Related articles
Data sources and methodology
| Place data | USPOTUS Atlas dataset (us-counties) - coordinates, hierarchy and facts. |
|---|---|
| Forecast and observations | Open-Meteo (ECMWF and national models). |
| Air quality and pollen | Copernicus CAMS via Open-Meteo. US AQI scale. |
| Climate averages | ERA5 reanalysis via the Open-Meteo archive, aggregated over 3 years. |
| Official alerts | US National Weather Service. |
| Method | Scores, comparisons and advice on this page are computed from the inputs above. Distances are straight-line. Nothing is estimated where data is missing - the block is simply not shown. |
Last updated August 22, 2026 at 7:45 AM local time. Live blocks refresh every 15 minutes; climate averages monthly.
