Frost dates · USDA zone 5b
Frost dates for Crystal Lake, IL
Crystal Lake, IL sees its last 32 °F night of spring around May 1 and its first of fall around October 11 — a 162-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 16 | Oct 24 |
| Median — 1 year in 2 | May 1 | Oct 11 |
| 1 year in 10 | May 19 | Sep 27 |
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: 162 days median, at least 142 in 9 years of 10, at least 181 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 19 and first of Oct 22.
Crystal Lake planting calendar, 2027
Every row runs from the median last frost (May 1) and median first frost (Oct 11) 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 6 | Apr 3 | Jul 22 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | May 1 | May 31 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Apr 17 | Apr 17 | Jun 1 | 45 from sow |
| Genovese BasilGenovese | Apr 3 | May 15 | Jul 14 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Mar 6 | May 8 | Jul 22 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Feb 20 | May 15 | Aug 18 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Mar 6 | May 8 | Jul 22 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Mar 6 | May 8 | Jul 27 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Mar 6 | May 8 | Jul 27 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Apr 17 | Apr 17 | Jun 26 | 70 from sow |
| TomatilloToma Verde | Mar 20 | May 8 | Jul 17 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Mar 20 | May 8 | Jul 22 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Mar 20 | May 8 | Jul 27 | 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 Crystal Lake grow?
Each sauce, scheduled for a Crystal Lake container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Crystal Lake frost questions
When is the last frost in Crystal Lake, IL?
The median last 32 °F freeze at MC HENRY -WG STRATTON L&D, IL is May 1: half of years see a later one. One year in ten, a freeze still comes after May 19; nine years in ten, it comes after April 16. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Crystal Lake, IL?
The median first 32 °F freeze of fall is October 11. One year in ten it arrives before September 27; nine years in ten, before October 24.
How long is the growing season in Crystal Lake, IL?
162 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 142 days; one year in ten, at least 181 days.
What growing zone is Crystal Lake, IL?
USDA hardiness zone 5b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 60014. 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 Crystal Lake, IL?
Start Roma VF (determinate paste) seeds indoors around Mar 20 and transplant around May 8, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for May 19. First ripe fruit lands around Jul 22.
When should I plant peppers in Crystal Lake, IL?
Sow jalapeño indoors on a heat mat around Mar 6; transplant no earlier than May 8, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Jul 22.
Nearby in Illinois
- Elginlast frost Apr 26
- Hoffman Estateslast frost Apr 30
- Palatinelast frost Apr 25
- Schaumburglast frost Apr 30
- Buffalo Grovelast frost Apr 19
- Arlington Heightslast frost Apr 19
All Illinois frost dates → · How frost-date math drives a sowing calendar →