ZIP 85301 Zone 9b

Arizona · USDA zone 9b, average annual extreme minimum 25°F to 30°F.

Nearest qualified station: YOUNGTOWN, AZ US (USC00029634), 8.2 miles from the Census ZCTA internal point for this ZIP.

Median last 32°F is January 20. Median first 32°F is December 15. The 50% growing-season length is 331 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%December 23Earlier date. A last 32°F on or after this day is common.
50%January 20Median.
10%February 18Later 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%November 28Earlier date. A first 32°F on or before this day is uncommon.
50%December 15Median.
90%January 7Later 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%358
50%331
90%297

28°F threshold

10%50%90%
Last, on or afterFebruary 1January 3December 13
First, on or beforeDecember 10December 29January 22
Season at least365 days365 days334 days

36°F threshold

10%50%90%
Last, on or afterMarch 4February 14January 21
First, on or beforeNovember 17December 2December 18
Season at least319 days291 days265 days

Station YOUNGTOWN, AZ US (USC00029634). 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 95.2%. Freeze dates are conditional on that threshold occurring. Elevation 345.9 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

Methodology · Arizona cities