Last Frost Date Chicago: Frost Dates, Late Frost Risk & Growing Season
When is the last spring frost and the first autumn frost in Chicago? Frost dates from 30 years of data, the risk of late frost, frost-free days and planting dates.
The frost season in Chicago
- Last frost (average): April 1
- In 1 year out of 10 it still freezes on April 9.
- First frost: November 11
- Frost-free season: 224 days
- Frost after 15 May: in 0 % of years
Frost days per month in Chicago
- January: 29.4 · -7 °C
- February: 25.2 · -5 °C
- March: 15.3 · 0 °C
- April: 1.3 · 5 °C
- May: 0 · 11 °C
- June: 0 · 17 °C
- July: 0 · 20 °C
- August: 0 · 19 °C
- September: 0 · 15 °C
- October: 0.2 · 8 °C
- November: 10.2 · 2 °C
- December: 25.7 · -4 °C
- Matched to the average lows of a weather station 18 km away – accurate to about ±1–2 weeks.
- Daily minimum temperatures 2 m above ground over 30 years (1991–2020), NASA POWER; station data: Deutscher Wetterdienst (CC BY 4.0). Ground frost can form while the air at 2 m is still +2 to +3 °C.