Chicago, Illinois Weather
Fireflies rise from the lawn. Day 76 of spring. Read this microseason across nine climate regions →
Chicago weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Overcast——81°50°—
- ThursdayJun 4Overcast——88°60°+7°
- FridayJun 5Light Drizzle61%—82°70°-6°
- SaturdayJun 6Showers61%0.09″75°64°-7°
- SundayJun 7Drizzle15%—76°58°+1°
- MondayJun 8Light Drizzle18%—79°63°+3°
- TuesdayJun 9Light Drizzle19%—79°68°0°
Ozone at AQI 46. AQI flat over the last 6 hours (within ±3 points). Overcast through the UV peak window (cloud cover ~100%) — afternoon ozone should stay flat.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 46. Overcast through the UV peak window (cloud cover ~100%) — afternoon ozone should stay flat.
- Present
- AQI 46
- UV peak
- 7.9 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 24
PM × Wind × Precip
PM2.5 at 7.4 µg/m³, PM10 at 8.2 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.90
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- background
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
The higher the clouds, the finer the weather.
- Moonrise
- 3:50 AM
- Moonset
- 12:42 PM
- In sign
- ♑︎ Capricorn
Fireflies rise from the lawn
Chicago at a glance
- Today vs. normal: 6°F above the seasonal normal for this latitude
- Last frost: April 27 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 3, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
SPC Convective Outlook
Storm Prediction Center — Chicago
SPC has placed Chicago in the General Thunderstorms category for severe thunderstorms day after tomorrow.
- TODAYNONENo severe risk
- TOMORROWNONENo severe risk
- DAY 3TSTMGeneral Thunderstorms
Thunderstorms possible. Not severe, but capable of producing lightning and brief heavy rain.
Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | lettuce, peas, spinach, radishes | — |
| May | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
July brings Chicago's warmest temperatures (~76°F mean) while January delivers the coldest (~26°F). Rainfall reaches its peak in May (4.1 inches) and drops to its lowest point in February (1.5 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 26° | 1.5″ | 3 |
| February | 30° | 1.5″ | 3 |
| March | 40° | 1.9″ | 5 |
| April | 51° | 3.6″ | 7 |
| May | 62° | 4.1″ | 8 |
| June | 72° | 4.0″ | 8 |
| July | 76° | 3.5″ | 6 |
| August | 75° | 4.0″ | 6 |
| September | 68° | 2.8″ | 5 |
| October | 55° | 3.5″ | 6 |
| November | 42° | 2.4″ | 5 |
| December | 31° | 1.8″ | 4 |
Regional context
Chicago belongs to a warm-summer humid continental climate region — sharing similar temperature ranges, seasonal patterns, and growing conditions with nearby cities in this zone.
Similar climates: Rockford, IL, Round Lake Beach, IL, Aurora, IL, Naperville, IL, Joliet, IL.
Naturalist notes
Late May brings the peak migration of warblers through Chicago's parks and lakefront areas.
Oak trees typically begin leafing out in early May as soil temperatures warm consistently above 45°F.
Frequently asked
- When does it freeze in Chicago?
- Chicago's last spring frost typically occurs around mid-April, and the first fall frost arrives around mid-November.
- What is the rainy season in Chicago?
- May receives the most rainfall with about 4.1 inches on average; the city gets roughly 34 inches annually.
- What is the warmest month in Chicago?
- July typically brings the warmest weather, averaging about 76°F.
- What is the coldest month in Chicago?
- January typically brings the coldest weather, averaging about 26°F.
- When can I start a vegetable garden in Chicago?
- Cool-season crops (peas, lettuce) can be planted around the last spring frost (mid-April); warm-season crops (tomatoes, peppers) should wait until 1–2 weeks after.
- How many rainy days does Chicago get?
- Chicago experiences about 68 rainy days per year on average.
- What hardiness zone is Chicago?
- Chicago's USDA hardiness zone depends on its lowest average winter temperature; use the USDA's online lookup with the city ZIP for the current zone designation.
Climate
Chicago, Illinois experiences a warm-summer humid continental climate zone. January temperatures hover near 26°F while July averages 76°F — a 50°F seasonal swing.
Throughout the year, Chicago receives about 34 inches of precipitation spread over roughly 68 rainy days.
Geography shapes Chicago's weather patterns through its latitude (41.8°N), proximity to large water bodies, and elevation — factors that determine what grows here, when frost is likely, and daily weather conditions.
ZIP codes in Chicago
- 60018
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