Frost dates / Arizona / Tempe

Frost dates in Tempe, AZ

The station on this page is TEMPE ASU, AZ US (USC00028499), 2.6 miles from the city point. Population in the Census 2024 estimate is 190,114.

Zone 10aUSDA average annual extreme minimum 30°F to 35°F, from ZIP 85282 (0.4 miles from the city point used on this page).

Median last 32°F is February 13. Median first 32°F is December 5. The 50% growing-season length is 298 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%	January 12	Earlier date. A last 32°F on or after this day is common.
50%	February 13	Median.
10%	March 9	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 18	Earlier date. A first 32°F on or before this day is uncommon.
50%	December 5	Median.
90%	December 24	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%	331
50%	298
90%	266

28°F threshold

	10%	50%	90%
Last, on or after	February 19	January 16	December 19
First, on or before	November 27	December 19	January 19
Season at least	365 days	337 days	299 days

36°F threshold

	10%	50%	90%
Last, on or after	April 7	March 8	February 14
First, on or before	November 7	November 26	December 9
Season at least	287 days	259 days	226 days

Station TEMPE ASU, AZ US (USC00028499). Completeness flag R, 24 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 99.7%. Freeze dates are conditional on that threshold occurring. Elevation 355.7 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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Tempe, AZ

Zone 10aAverage annual extreme minimum 30°F to 35°F

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

Arizona. Nearest qualified station: TEMPE ASU, AZ US (USC00028499), 2.6 miles. Median last 32°F February 13. Median first 32°F December 5. The 50% growing-season length is 298 days.

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32°F probabilities at this station

	10%	50%	90%
Last 32°F on or after	March 9	February 13	January 12
First 32°F on or before	November 18	December 5	December 24

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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