ZIP 62523 Zone 6a

Illinois · USDA zone 6a, average annual extreme minimum -10°F to -5°F.

Nearest qualified station: DECATUR WTP, IL US (USC00112193), 1 miles from the Census ZCTA internal point for this ZIP.

Median last 32°F is April 14. Median first 32°F is October 24. The 50% growing-season length is 192 days. The green band runs from the median last frost to the median first frost. Thin ticks mark the 10%, 50%, and 90% dates.

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Last 32°F in spring

NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.

ProbabilityDateHow to read it
90%April 1Earlier date. A last 32°F on or after this day is common.
50%April 14Median.
10%May 1Later date. A last 32°F on or after this day is uncommon.

First 32°F in fall

NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.

ProbabilityDateHow to read it
10%October 11Earlier date. A first 32°F on or before this day is uncommon.
50%October 24Median.
90%November 5Later date. A first 32°F on or before this day is common.

32°F growing-season length

Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.

Probability the season is at least this longDays
10%211
50%192
90%171

28°F threshold

10%50%90%
Last, on or afterApril 17April 3March 18
First, on or beforeOctober 20November 3November 19
Season at least237 days214 days195 days

36°F threshold

10%50%90%
Last, on or afterMay 13April 26April 12
First, on or beforeSeptember 30October 14October 27
Season at least190 days170 days147 days

Station DECATUR WTP, IL US (USC00112193). Completeness flag R, 24 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 100%. Freeze dates are conditional on that threshold occurring. Elevation 194.8 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

Methodology · Illinois cities