Frost dates / Arizona / Glendale

Frost dates in Glendale, AZ

The station on this page is YOUNGTOWN, AZ US (USC00029634), 7.7 miles from the city point. Population in the Census 2024 estimate is 258,143.

Zone 9bUSDA average annual extreme minimum 25°F to 30°F, from ZIP 85301 (0.7 miles from the city point used on this page).

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.

Probability	Date	How to read it
90%	December 23	Earlier date. A last 32°F on or after this day is common.
50%	January 20	Median.
10%	February 18	Later 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.

Probability	Date	How to read it
10%	November 28	Earlier date. A first 32°F on or before this day is uncommon.
50%	December 15	Median.
90%	January 7	Later 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 long	Days
10%	358
50%	331
90%	297

28°F threshold

	10%	50%	90%
Last, on or after	February 1	January 3	December 13
First, on or before	December 10	December 29	January 22
Season at least	365 days	365 days	334 days

36°F threshold

	10%	50%	90%
Last, on or after	March 4	February 14	January 21
First, on or before	November 17	December 2	December 18
Season at least	319 days	291 days	265 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.

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Glendale, AZ

Zone 9bAverage annual extreme minimum 25°F to 30°F

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

Arizona. Nearest qualified station: YOUNGTOWN, AZ US (USC00029634), 7.7 miles. Median last 32°F January 20. Median first 32°F December 15. The 50% growing-season length is 331 days.

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32°F probabilities at this station

	10%	50%	90%
Last 32°F on or after	February 18	January 20	December 23
First 32°F on or before	November 28	December 15	January 7

Column order matches the NCEI file: for the last freeze, 10% is the later date and 90% is the earlier date. How to read the probabilities.

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Planting calendar

Frost dates for Arizona are above. Planting windows appear for states with a cited extension guide. The fall and seed tools use the numbers you enter and the station dates.

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