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Illinois · NOAA station USC00117187

Frost dates for Rend Lake Dam, IL

At Rend Lake Dam, the median last spring frost (32°F) is Apr 4 and the median first fall frost is Oct 27, for a typical growing season of 204 days. For a 90% chance that the last frost has passed, wait until Apr 19. Nearby ZIP codes are in USDA hardiness zones 6b to 7a.

  • Apr 4Last spring frost (median)50% chance of 32°F after this date
  • Apr 19Safer planting date10% chance of 32°F after this date
  • Oct 27First fall frost (median)50% chance of 32°F by this date
  • 204 daysGrowing season (median)between 32°F freezes

Planting date calculator

Pick how much frost risk you accept and how many weeks before or after the last frost your seed packet says to plant.

From your seed packet, e.g. “start 6 weeks before last frost”.

–Last spring frost
–First fall frost
–Your planting date
–Hardiness zone

Last spring frost dates

The chance that the temperature drops to the threshold after each date.

Rend Lake Dam: last spring freeze by temperature
Temperature90% chance later50% chance later10% chance later
36°FMar 31Apr 15May 1
32°FMar 21Apr 4Apr 19
28°FMar 10Mar 26Apr 9
24°FFeb 28Mar 15Mar 30

First fall frost dates

The chance that the temperature has dropped to the threshold by each date.

Rend Lake Dam: first fall freeze by temperature
Temperature10% chance by50% chance by90% chance by
36°FOct 5Oct 18Oct 28
32°FOct 16Oct 27Nov 8
28°FOct 25Nov 5Nov 23
24°FNov 2Nov 16Dec 4

Growing season length

Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.

Rend Lake Dam: growing season by temperature
Temperature9 in 10 years at least5 in 10 years at least1 in 10 years at least
36°F163 days183 days202 days
32°F185 days204 days222 days
28°F203 days223 days246 days
24°F223 days245 days269 days

Chance of a freeze in any year

Rend Lake Dam: probability of at least one day at or below each temperature
TemperatureChance per year
36°F100%
32°F100%
28°F100%
24°F100%

ZIP codes whose closest station is this one

ZIP codes near Rend Lake Dam with 2023 USDA hardiness zones
ZIPHardiness zoneAvg. extreme lowDistance
628917a0 to 5°F5 km
628846b-5 to 0°F7 km
628197a0 to 5°F7 km
628257a0 to 5°F8 km
628227a0 to 5°F9 km
628747a0 to 5°F14 km
628836b-5 to 0°F17 km
628946b-5 to 0°F19 km
628417a0 to 5°F20 km

Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.

About this station

  • NOAA station ID USC00117187, at 38.0406, -88.9883, elevation 139 m (455 ft).
  • Data quality: Estimated from nearby stations (2+ years), 8 years of freeze data.
  • Average days per year at or below 32°F: 100.
  • Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.

Nearby weather stations

Sources

Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.

All Illinois stations · How frost dates are calculated