ZIP 80238 Zone 6a

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

Nearest qualified station: DENVER-STAPLETON, CO US (USW00023062), 1.1 miles from the Census ZCTA internal point for this ZIP.

Median last 32°F is May 4. Median first 32°F is October 8. The 50% growing-season length is 156 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 20Earlier date. A last 32°F on or after this day is common.
50%May 4Median.
10%May 16Later 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%September 25Earlier date. A first 32°F on or before this day is uncommon.
50%October 8Median.
90%October 20Later 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%175
50%156
90%138

28°F threshold

10%50%90%
Last, on or afterMay 7April 22April 6
First, on or beforeOctober 3October 18October 31
Season at least198 days177 days158 days

36°F threshold

10%50%90%
Last, on or afterMay 26May 12May 2
First, on or beforeSeptember 16October 1October 13
Season at least156 days140 days121 days

Station DENVER-STAPLETON, CO US (USW00023062). Completeness flag S, 28 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 1611.2 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

Methodology · Colorado cities