San Tan Valley, AZ weather in December
In December, San Tan Valley sees highs around 67°F and lows around 36°F: mild and mostly dry. Rain falls on about 4 days. It is one of the coolest months in San Tan Valley. Great for outdoor plans.
- Normal high
- 67°F
- Normal low
- 36°F
- Wet days
- 4
- 0.8 in total
- Muggy days
- 0
- dew point 65°F+
How December changes from start to finish
| December 1 | December 31 | |
|---|---|---|
| Normal high | 71°F | 66°F |
| Normal low | 38°F | 36°F |
| Chance of a wet day | 11% | 13% |
| Sunrise / sunset | 7:11 am / 5:18 pm | 7:29 am / 5:28 pm |
| Daylight | 10.1 h | 10.0 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Arizona time (no daylight saving)).
A typical December day
- 6 am47°Fdew point 33°F
- 9 am51°Fdew point 33°F
- Noon61°Fdew point 30°F
- 3 pm65°Fdew point 29°F
- 6 pm62°Fdew point 31°F
- 9 pm56°Fdew point 33°F
NOAA hourly normals (local standard time) from Phoenix Sky Harbor Intl Airport (32 mi away); average wind 5 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F20 of 31
- Hot dayshigh 90°F or more0 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow4 of 31
- Notable rainat least 0.10 in3 of 31
- Freezing nightslow 32°F or below12 of 31
Average days per December, counted from daily records for each year 1991-2020.
Rain in December
Normal precipitation is 0.8 in; a dry December brings about 0.08 in and a wet one about 1.2 in (25th and 75th percentiles). About 1 day brings half an inch or more. Snow is very rare.
How December varies from year to year
- Warmest December, 1991-20202017: average high 73°F
- Coolest December2007: average high 62°F
- Wettest December1994: 2.7 in
- Driest December1996: no measurable precipitation
- Highest reading86°F (December 1, 1999)
- Lowest reading17°F (December 24, 1998)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
December compared with November and January
| November | December | January | |
|---|---|---|---|
| Normal high | 78°F | 67°F | 68°F |
| Normal low | 44°F | 36°F | 37°F |
| Wet days | 2 | 4 | 4 |
| Comfortable days | 16 | 20 | 20 |
| Daylight | 10.5 h | 10.0 h | 10.2 h |
Highs change by -11°F from November and +1°F into January.
Nearby alternatives in December
- Cooler: Sedona, AZ117 mi · high 58°F · 4 wet days
How San Tan Valley ranks in December
- Normal high48th warmest of 378 cities; 2nd of 13 in Arizona
- Wet days27th driest of 378
- Comfortable days6th most of 340
What to pack for San Tan Valley in December
- A warm jacket – lows near 36°F, highs near 67°F
- Layers – afternoons near 67°F but nights near 36°F
Frost in December
The first fall frost typically comes around Dec 11; in 1 year in 10 it comes before Nov 23. All frost dates for San Tan Valley.
Heating and cooling
December has 416 heating degree days and 0 cooling degree days (base 65°F), 8% of the year's total heating and cooling demand.
Questions
How cold is San Tan Valley in December?
The normal high is 67°F and the normal low is 36°F. From 1991 to 2020 the coldest December reading was 17°F (December 24, 1998).
Does it rain a lot in San Tan Valley in December?
About 4 days in December have at least 0.01 in of precipitation, and the normal total is 0.8 in. The wettest December in 1991-2020 was in 1994 (2.7 in); the driest was in 1996, with no measurable precipitation.
Does it snow in San Tan Valley in December?
Snow is very rare: the 1991-2020 normal for December rounds to 0.0 in.
Is December a good time to visit San Tan Valley?
December ranks 3rd of 12 months on our comfort score for San Tan Valley (71 out of 100). It has about 20 comfortable days. The best months are January, February and December.
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).