Sunnyvale, CA weather in January
Sunnyvale is cool in January, with frequent rain: highs average 59°F and nights drop to about 42°F. Rain falls on about 11 days. It is one of the coolest months in Sunnyvale.
- Normal high
- 59°F
- Normal low
- 42°F
- Wet days
- 11
- 2.5 in total
- Muggy days
- 0
- dew point 65°F+
How January changes from start to finish
| January 1 | January 31 | |
|---|---|---|
| Normal high | 58°F | 60°F |
| Normal low | 42°F | 43°F |
| Chance of a wet day | 35% | 36% |
| Sunrise / sunset | 7:22 am / 5:00 pm | 7:12 am / 5:31 pm |
| Daylight | 9.6 h | 10.3 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Pacific Time).
A typical January day
- 6 am47°Fdew point 43°F
- 9 am50°Fdew point 44°F
- Noon53°Fdew point 45°F
- 3 pm55°Fdew point 45°F
- 6 pm53°Fdew point 45°F
- 9 pm51°Fdew point 45°F
NOAA hourly normals (local standard time) from San Francisco Intl Airport (25 mi away); average wind 7 mph; clear or few clouds in 29% of daytime hours, mostly cloudy or overcast in 57%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F5 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 snow11 of 31
- Notable rainat least 0.10 in5 of 31
- Freezing nightslow 32°F or below1 of 31
Average days per January, counted from daily records for each year 1991-2020.
Rain in January
Normal precipitation is 2.5 in; a dry January brings about 0.9 in and a wet one about 3.8 in (25th and 75th percentiles). About 2 days bring half an inch or more. Snow is very rare.
How January varies from year to year
- Warmest January, 1991-20202014: average high 66°F
- Coolest January2008: average high 55°F
- Wettest January1993: 6.0 in
- Driest January2015: no measurable precipitation
- Highest reading74°F (January 22, 2014)
- Lowest reading27°F (January 15, 2007)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
January compared with December and February
| December | January | February | |
|---|---|---|---|
| Normal high | 59°F | 59°F | 62°F |
| Normal low | 42°F | 42°F | 45°F |
| Wet days | 11 | 11 | 11 |
| Comfortable days | 4 | 5 | 8 |
| Daylight | 9.6 h | 9.9 h | 10.8 h |
Highs change by 0°F from December and +3°F into February.
Nearby alternatives in January
- Warmer: Santa Maria, CA189 mi · high 65°F · 8 wet days
- Drier: Fresno, CA132 mi · high 55°F · 8 wet days
- Cooler: Yosemite Valley, CA137 mi · high 48°F · 9 wet days
How Sunnyvale ranks in January
- Normal high110th warmest of 378 cities; 35th of 60 in California
- Wet days265th driest of 378
- Comfortable days125th most of 339
What to pack for Sunnyvale in January
- A rain jacket or umbrella – rain on about 11 days
Frost in January
The last spring frost typically comes around Jan 6; in 1 year in 10 it comes after Feb 4. All frost dates for Sunnyvale.
Heating and cooling
January has 443 heating degree days and 0 cooling degree days (base 65°F), 16% of the year's total heating and cooling demand.
Questions
How cold is Sunnyvale in January?
The normal high is 59°F and the normal low is 42°F. From 1991 to 2020 the coldest January reading was 27°F (January 15, 2007).
Does it rain a lot in Sunnyvale in January?
About 11 days in January have at least 0.01 in of precipitation, and the normal total is 2.5 in. The wettest January in 1991-2020 was in 1993 (6.0 in); the driest was in 2015, with no measurable precipitation.
Is January a good time to visit Sunnyvale?
January ranks 11th of 12 months on our comfort score for Sunnyvale (50 out of 100). It has about 5 comfortable days. The best months are May, June and July.
Where the numbers come from
- Temperature, rain and frost dates: Moffett Federal Airfield (USW00023244), 2.6 mi NNW of the city center, 39 ft (85 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Snowfall: Palo Alto (USC00046646), 7.7 mi NW of the city center, 25 ft (99 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Snow depth: Newark (USC00046144), 10 mi N of the city center, 10 ft (114 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour and cloud cover: San Francisco Intl Airport (USW00023234), 25 mi NW of the city center, 8 ft (116 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: N Y. Mineta Sn Jo Intl Apt (724945-23293), 6.2 mi E of the city center, 49 ft (75 ft lower than the city). Hourly observations, 1991-2020.