ZIP 80241 Zone 6a

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

Nearest qualified station: NORTHGLENN, CO US (USC00055984), 3.8 miles from the Census ZCTA internal point for this ZIP.

Median last 32°F is May 2. Median first 32°F is October 11. The 50% growing-season length is 160 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 18Earlier date. A last 32°F on or after this day is common.
50%May 2Median.
10%May 14Later 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 26Earlier date. A first 32°F on or before this day is uncommon.
50%October 11Median.
90%October 24Later 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%180
50%160
90%142

28°F threshold

10%50%90%
Last, on or afterMay 5April 20April 4
First, on or beforeOctober 7October 21November 4
Season at least204 days182 days160 days

36°F threshold

10%50%90%
Last, on or afterMay 26May 12April 30
First, on or beforeSeptember 18October 1October 14
Season at least159 days142 days122 days

Station NORTHGLENN, CO US (USC00055984). Completeness flag S, 26 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 1648.1 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