Frost dates · USDA zone 6a
Frost dates for Waukegan, IL
Waukegan, IL sees its last 32 °F night of spring around April 30 and its first of fall around October 19 — a 170-day freeze-free season in a typical year.
Pick a sauce; the Plan Builder runs this station's dates and hands back the calendar, plant count and gear list.
Freeze odds, by date
| Odds | Last spring freeze after | First fall freeze before |
|---|---|---|
| 9 years in 10 | Apr 15 | Nov 3 |
| Median — 1 year in 2 | Apr 30 | Oct 19 |
| 1 year in 10 | May 14 | Sep 30 |
The top row is the risky edge: in 9 years of 10 a spring freeze still comes after it, so tender transplants set out then need cover. The bottom row is the cautious date — only 1 year in 10 freezes after it — and the one to plan uncovered tender transplants against. Freeze-free season: 170 days median, at least 150 in 9 years of 10, at least 190 days in 1 year of 10. NOAA ranks season length year by year, so it is not the gap between two rows above. A hard freeze (28 °F) has a median last date of Apr 20 and first of Oct 30.
Waukegan planting calendar, 2027
Every row runs from the median last frost (Apr 30) and median first frost (Oct 19) above, using each cultivar's days to maturity. Same engine as the Plan Builder.
| Crop | Start indoors | Transplant / plant | First harvest | Days |
|---|---|---|---|---|
| Hardneck GarlicSiberian (porcelain hardneck) | — | Oct 15prior fall | Jun 12 | 240 from sow |
| Spanish OnionYellow Sweet Spanish (long-day) | Feb 5 | Apr 2 | Jul 21 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Apr 30 | May 30 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Apr 16 | Apr 16 | May 31 | 45 from sow |
| Genovese BasilGenovese | Apr 2 | May 14 | Jul 13 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Mar 5 | May 7 | Jul 21 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Feb 19 | May 14 | Aug 17 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Mar 5 | May 7 | Jul 21 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Mar 5 | May 7 | Jul 26 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Mar 5 | May 7 | Jul 26 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Apr 16 | Apr 16 | Jun 25 | 70 from sow |
| TomatilloToma Verde | Mar 19 | May 7 | Jul 16 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Mar 19 | May 7 | Jul 21 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Mar 19 | May 7 | Jul 26 | 80 from transplant |
Tight means first harvest lands within two weeks of the median first fall frost: start that crop indoors on time or cover it in fall.
What sauce can Waukegan grow?
Each sauce, scheduled for a Waukegan container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Waukegan frost questions
When is the last frost in Waukegan, IL?
The median last 32 °F freeze at WAUKEGAN, IL is April 30: half of years see a later one. One year in ten, a freeze still comes after May 14; nine years in ten, it comes after April 15. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Waukegan, IL?
The median first 32 °F freeze of fall is October 19. One year in ten it arrives before September 30; nine years in ten, before November 3.
How long is the growing season in Waukegan, IL?
170 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 150 days; one year in ten, at least 190 days.
What growing zone is Waukegan, IL?
USDA hardiness zone 6a, per the 2023 USDA Plant Hardiness Zone Map for ZIP 60085. A zone describes the coldest winter night, not when frost ends, so it is the wrong number for a planting calendar — the frost dates on this page are the right one.
When should I plant tomatoes in Waukegan, IL?
Start Roma VF (determinate paste) seeds indoors around Mar 19 and transplant around May 7, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for May 14. First ripe fruit lands around Jul 21.
When should I plant peppers in Waukegan, IL?
Sow jalapeño indoors on a heat mat around Mar 5; transplant no earlier than May 7, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Jul 21.
Nearby in Illinois
- Buffalo Grovelast frost Apr 19
- Palatinelast frost Apr 25
- Arlington Heightslast frost Apr 19
- Glenviewlast frost Apr 19
- Mount Prospectlast frost Apr 19
- Des Plaineslast frost Apr 16
All Illinois frost dates → · How frost-date math drives a sowing calendar →