Climateby Month

San Tan Valley, AZ climate by month

NOAA 1991-2020 normals · 1,522 ft elevation

San Tan Valley has very hot summers and mild winters. Highs peak at 107°F in July and fall to 67°F in December. The wettest month is August (about 5 wet days) and the driest is June (about 1). Snow is rare. By our comfort score the best months are January, February and December.

Warmest month
107°F
July normal high
Coldest month
36°F
December normal low
Wet days a year
37
8.3 in of precipitation
Muggy days a year
12
dew point 65°F or higher

How warm is San Tan Valley?

Normal highs range from 67°F in December to 107°F in July.

20°40°60°80°100°120° January: normal high 68°F (20°C), low 37°F (3°C) February: normal high 71°F (22°C), low 40°F (4°C) March: normal high 78°F (26°C), low 45°F (7°C) April: normal high 86°F (30°C), low 51°F (11°C) May: normal high 95°F (35°C), low 59°F (15°C) June: normal high 105°F (41°C), low 68°F (20°C) July: normal high 107°F (42°C), low 77°F (25°C) 107° 77° August: normal high 105°F (41°C), low 77°F (25°C) September: normal high 101°F (38°C), low 70°F (21°C) October: normal high 91°F (33°C), low 56°F (13°C) November: normal high 78°F (26°C), low 44°F (7°C) December: normal high 67°F (19°C), low 36°F (2°C) 67° 36° JFMAMJJASOND

Bars run from the normal low to the normal high for each month.

How rainy is San Tan Valley?

August has the most wet days (about 5); the year brings about 8.3 in of precipitation.

January: 4 wet days February: 4 wet days March: 3 wet days April: 1 wet days May: 1 wet days June: 1 wet days 1 July: 5 wet days August: 5 wet days 5 September: 3 wet days October: 2 wet days November: 2 wet days December: 4 wet days JFMAMJJASOND

Wet day: at least 0.01 in of rain or melted snow, counted from daily records 1991-2020.

How humid is San Tan Valley?

Muggy days peak in August, at about 5 days.

January: 0 muggy days 0 February: 0 muggy days March: 0 muggy days April: 0 muggy days May: 0 muggy days June: 0 muggy days July: 4 muggy days August: 5 muggy days 5 September: 2 muggy days October: 0 muggy days November: 0 muggy days December: 0 muggy days JFMAMJJASOND

Muggy day: daily mean dew point of 65°F or higher, from hourly observations 1991-2020 at Phoenix Sky Harbor Intl Airport, 32 mi WNW of the city center (the nearest airport with complete hourly records).

How much daylight?

Daylight ranges from about 10.0 hours in December to 14.3 hours in June.

January: 10.2 hours of daylight February: 11.0 hours of daylight March: 12.0 hours of daylight April: 13.0 hours of daylight May: 13.9 hours of daylight June: 14.3 hours of daylight 14.3 July: 14.1 hours of daylight August: 13.3 hours of daylight September: 12.4 hours of daylight October: 11.3 hours of daylight November: 10.5 hours of daylight December: 10.0 hours of daylight 10.0 JFMAMJJASOND
See all numbers
Monthly climate normals and day counts for San Tan Valley, 1991-2020
MonthHighLowPrecip.Wet daysMuggy daysDaylight
January 68°F37°F 1.0 in4 0 10.2 h
February 71°F40°F 1.0 in4 0 11.0 h
March 78°F45°F 0.9 in3 0 12.0 h
April 86°F51°F 0.3 in1 0 13.0 h
May 95°F59°F 0.2 in1 0 13.9 h
June 105°F68°F 0.06 in1 0 14.3 h
July 107°F77°F 1.1 in5 4 14.1 h
August 105°F77°F 1.2 in5 5 13.3 h
September 101°F70°F 0.7 in3 2 12.4 h
October 91°F56°F 0.5 in2 0 11.3 h
November 78°F44°F 0.5 in2 0 10.5 h
December 67°F36°F 0.8 in4 0 10.0 h

High and low: NOAA 1991-2020 normal daily high and low. Wet days: at least 0.01 in of rain or melted snow. Muggy days: daily mean dew point 65°F or higher.

Best months to visit San Tan Valley

By our comfort score, the best months are January, February and December.

Comfort score by month (0-100) and its parts, in days per month
MonthScoreComfortableNotable rainHot or cold
Jan 722020
Feb 731830
Mar 681523
Apr 557112
May 421125
Jun 380030
Jul 360331
Aug 340331
Sep 330229
Oct 423119
Nov 671612
Dec 712030

Score = 40 × share of comfortable days + 25 × share of days without notable rain + 20 × share of days neither hot (90°F+) nor cold (high 40°F or below) + 15 × daylight. How the score works.

Frost dates in San Tan Valley

The last spring frost typically comes around Feb 1, and the first fall frost around Dec 11, leaving 315 frost-free days in a typical year.

Frost and freeze dates for San Tan Valley
Typical date1 year in 10
Last spring frost (32°F)Feb 1after Feb 27
First fall frost (32°F)Dec 11before Nov 23
Last hard freeze (28°F)Jan 8after Feb 11
First hard freeze (28°F)Dec 26before Dec 4
Frost-free season315 daysunder 281 days

"Typical" is the date with a 50% chance of a later spring frost (or earlier fall frost). Planting after the "1 year in 10" spring date gives a 90% chance of no further frost. The Old Farmer's Almanac publishes 30% dates, which fall between our typical and 1-in-10 dates.

Station: Chandler Heights (USC00021514), NOAA 1991-2020 freeze probabilities. Frost dates for every city in Arizona.

Hottest and coldest readings, 1991-2020

The highest reading was 123°F (June 30, 1994); the lowest was 14°F (January 15, 2013).

From the temperature station's daily records with NOAA quality flags removed. Not an all-time record.

Near San Tan Valley

Similar climates elsewhere

Where the numbers come from

  • Temperature, rain, snowfall and snow depth: Casa Grande Nm (USC00021314), 14 mi S of the city center, 1,419 ft (103 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Frost dates: Chandler Heights (USC00021514), 9.0 mi W of the city center, 1,425 ft (97 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Humidity and wind by hour: Phoenix Sky Harbor Intl Airport (USW00023183), 32 mi WNW of the city center, 1,107 ft (415 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Daily humidity and wind: Phoenix Sky Harbor Intl Airport (722780-23183), 32 mi WNW of the city center, 1,113 ft (409 ft lower than the city). Hourly observations, 1991-2020.
  • Not available for this location: cloud cover (no station close enough or similar enough in elevation).

Distances from the city center (USGS). Methodology · Report an error