Sunnyvale, CA weather in August
In August, Sunnyvale sees highs around 77°F and lows around 59°F: mild and dry. Rain is rare. Great for outdoor plans.
- Normal high
- 77°F
- Normal low
- 59°F
- Wet days
- 0
- 0.01 in total
- Muggy days
- 0
- dew point 65°F+
How August changes from start to finish
| August 1 | August 31 | |
|---|---|---|
| Normal high | 76°F | 78°F |
| Normal low | 59°F | 58°F |
| Chance of a wet day | 1% | 1% |
| Sunrise / sunset | 6:12 am / 8:16 pm | 6:37 am / 7:39 pm |
| Daylight | 14.1 h | 13.0 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 August day
- 6 am58°Fdew point 54°F
- 9 am64°Fdew point 55°F
- Noon70°Fdew point 55°F
- 3 pm70°Fdew point 54°F
- 6 pm64°Fdew point 54°F
- 9 pm60°Fdew point 54°F
NOAA hourly normals (local standard time) from San Francisco Intl Airport (25 mi away); average wind 12 mph; clear or few clouds in 65% of daytime hours, mostly cloudy or overcast in 17%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F23 of 31
- Hot dayshigh 90°F or more2 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow0 of 31
- Notable rainat least 0.10 in0 of 31
- Freezing nightslow 32°F or below0 of 31
Average days per August, counted from daily records for each year 1991-2020.
Rain in August
Normal precipitation is 0.01 in; a dry August brings about 0.0 in and a wet one about 0.0 in (25th and 75th percentiles). Days with half an inch or more are rare.
How August varies from year to year
- Warmest August, 1991-20202019: average high 82°F
- Coolest August2010: average high 74°F
- Wettest August1991: 0.09 in
- Driest August1992: no measurable precipitation
- Highest reading101°F (August 28, 2009)
- Lowest reading51°F (August 20, 2000)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
August compared with July and September
| July | August | September | |
|---|---|---|---|
| Normal high | 77°F | 77°F | 78°F |
| Normal low | 59°F | 59°F | 57°F |
| Wet days | 0 | 0 | 1 |
| Comfortable days | 24 | 23 | 21 |
| Daylight | 14.4 h | 13.6 h | 12.4 h |
Highs change by 0°F from July and +1°F into September.
Nearby alternatives in August
- Warmer: Concord, CA42 mi · high 87°F · 0 wet days
- Cooler: San Francisco, CA35 mi · high 68°F · 1 wet day
How Sunnyvale ranks in August
- Normal high345th warmest of 378 cities; 51st of 60 in California
- Wet days27th driest of 378
- Comfortable days10th most of 341
Heating and cooling
August has 8 heating degree days and 99 cooling degree days (base 65°F), 4% of the year's total heating and cooling demand.
Questions
How hot is Sunnyvale in August?
The normal high is 77°F and the normal low is 59°F. From 1991 to 2020 the hottest August reading was 101°F (most recently on August 28, 2009).
Does it rain a lot in Sunnyvale in August?
About 0 days in August have at least 0.01 in of precipitation, and the normal total is 0.01 in. The wettest August in 1991-2020 was in 1991 (0.09 in); the driest was in 1992, with no measurable precipitation.
Is August a good time to visit Sunnyvale?
August ranks 4th of 12 months on our comfort score for Sunnyvale (86 out of 100). It has about 23 comfortable days and about 2 days at 90°F or hotter. 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.