Frost dates / Arizona / Oro Valley

Frost dates in Oro Valley, AZ

The station on this page is CATALINA SP, AZ US (USC00021357), 2.7 miles from the city point. Population in the Census 2024 estimate is 48,855.

Zone 9aUSDA average annual extreme minimum 20°F to 25°F, from ZIP 85737 (1.8 miles from the city point used on this page).

Median last 32°F is April 2. Median first 32°F is November 11. The 50% growing-season length is 222 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%	March 16	Earlier date. A last 32°F on or after this day is common.
50%	April 2	Median.
10%	April 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%	October 26	Earlier date. A first 32°F on or before this day is uncommon.
50%	November 11	Median.
90%	November 29	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%	245
50%	222
90%	196

28°F threshold

	10%	50%	90%
Last, on or after	April 1	March 12	February 22
First, on or before	November 3	November 21	December 10
Season at least	278 days	252 days	226 days

36°F threshold

	10%	50%	90%
Last, on or after	May 5	April 18	April 4
First, on or before	October 18	November 1	November 17
Season at least	218 days	195 days	173 days

Station CATALINA SP, AZ US (USC00021357). Completeness flag R, 13 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 825.1 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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Oro Valley, AZ

Zone 9aAverage annual extreme minimum 20°F to 25°F

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

Arizona. Nearest qualified station: CATALINA SP, AZ US (USC00021357), 2.7 miles. Median last 32°F April 2. Median first 32°F November 11. The 50% growing-season length is 222 days.

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32°F probabilities at this station

	10%	50%	90%
Last 32°F on or after	April 18	April 2	March 16
First 32°F on or before	October 26	November 11	November 29

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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