ZIP 80528 Zone 5b

Colorado · USDA zone 5b, average annual extreme minimum -15°F to -10°F.

Nearest qualified station: FT COLLINS 4 E, CO US (USC00053006), 5.4 miles from the Census ZCTA internal point for this ZIP.

Median last 32°F is May 3. Median first 32°F is October 6. The 50% growing-season length is 154 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 21Earlier date. A last 32°F on or after this day is common.
50%May 3Median.
10%May 15Later 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 22Earlier date. A first 32°F on or before this day is uncommon.
50%October 6Median.
90%October 17Later 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%171
50%154
90%135

28°F threshold

10%50%90%
Last, on or afterMay 8April 23April 8
First, on or beforeSeptember 30October 14October 26
Season at least192 days174 days153 days

36°F threshold

10%50%90%
Last, on or afterMay 26May 14May 3
First, on or beforeSeptember 13September 27October 8
Season at least151 days136 days118 days

Station FT COLLINS 4 E, CO US (USC00053006). Completeness flag S, 29 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 1499.6 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