Weather in Chicago, Illinois
Roses open along the stoops. Day 59 of spring. Read this microseason across nine climate regions →
When the dew is on the grass, rain will never come to pass.
- Moonrise
- 10:33 AM
- Moonset
- 1:36 AM
- In sign
- ♊︎ Gemini
Roses open along the stoops
Chicago at a glance
- Today vs. normal: NaN°F below the seasonal normal for this latitude
- Last frost: April 27 (climatological average for this latitude)
- Microseason: 28 of 72, May 16–20
- Planting window: Direct sow okra, melons, and southern peas. Thin carrot rows.
Right now in the garden
Warm-season window is open
As of May 17, the last spring frost has passed for most years. Transplant tomatoes, peppers, eggplants, basil, and cucurbits (cucumbers, squash, melons) now. Direct-sow beans and corn into warm soil.
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
- 60649
- 60641
- 60640
- 60643
- 60642
- 60645
- 60644
- 60647
- 60646
- 60616
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- 60615
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- 60707
- 60499
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- 60689
- 60690
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- 60696
- 60699