Sunnyvale Weather
Town • San Francisco Bay Area
Sunnyvale spreads across the open floor of the Santa Clara Valley. Its grid of neighborhoods and tech campuses runs from the El Camino Real corridor north to the Bay's salt ponds and Moffett Field. Its Murphy Avenue downtown sits beside the Caltrain station on Evelyn Avenue. At the Bay edge, Sunnyvale Baylands Park pairs lawns and picnic groves with more than a hundred acres of restored seasonal wetlands. Reclaimed water from the city's water pollution control plant keeps them wet.
Plan your week
10-Day Forecast
Hour by hour
Hourly Forecast
Current Conditions
Comfort Breakdown
Sunnyvale weather today and through the year
It's 53°F at Sunnyvale right now (feels like 50°F), with 7 mph wind and a comfort score of 77. Monday's forecast high at Sunnyvale is 56°F, 10°F below the mid November normal of 66°F. The best window today is 10 AM to 1 PM, at about 54°F with a 3 mph wind (comfort 62).
August is the warmest month at Sunnyvale, with an average high of 82°F. December is the coldest, with an average low of 40°F. February is the wettest month (3.8 in.), out of about 18.4 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Sunnyvale are September, June, and July. The best hours are usually 10 AM to 1 PM in September, 10 AM to 1 PM in June, and 10 AM to 1 PM in July.
Sunnyvale sits farther from the foothills than Los Altos or Cupertino and farther down the Bay than Palo Alto, out on the open valley floor. Summer days follow the valley pattern almost like clockwork. The air stays still from evening until around midday, and then a northwest sea breeze blows off the Bay through the afternoon. Along the Baylands that breeze can turn strong late in the day.
Forecast updated November 15, 2026 at 4:00 AM PST. Climate figures come from NOAA 1991-2020 normals. Hourly patterns come from NOAA's HRRR hourly analysis from September 2014 to April 2026.
What to expect at Sunnyvale in the next few days
No active National Weather Service alerts for this location.
Best time to go
The best window today is 10 AM to 1 PM, at about 54°F with a 3 mph wind (comfort 62).
Best day this week
Of the next 7 days, Friday looks best for Sunnyvale, with a 60°F high and midday comfort near 74. Wednesday looks weakest (50).
Rain
Next good chance of rain: today (88%, about 0.26 in.).
Live weather map
Weather around Sunnyvale right now
Overcast and 53° at Sunnyvale right now.
About the live weather map for Sunnyvale
The map centers on Sunnyvale and stacks fog, satellite clouds, and precipitation radar on one view. Clouds come from the GOES-West satellite and rain from NOAA radar, and both show current conditions. Fog comes from our HRRR-based fog model, and the slider steps through its forecast for the next 12 hours.
Dots mark nearby places with their current temperature, colored by comfort score. Use the layer buttons to turn any layer off, or open the full map for every destination in the region.
Nearby Temperature Comparison
Conditions at nearby San Francisco Bay Area destinations
Tip: Bay Area temperatures can change by 20 to 30°F over a short distance because of microclimates.
Sunnyvale vs nearby places
Typical summer conditions compared with Sunnyvale, from the same NOAA HRRR hourly record. The list shows the closest places, then nearby places whose climate differs the most.
| Place | Distance | Summer afternoons | Morning fog | Afternoon wind | Compared with Sunnyvale |
|---|---|---|---|---|---|
| Mountain View | 2.9 mi | -1°F | 17% | 10 mph | a very similar climate |
| Cupertino | 3.2 mi | +4°F | 12% | 9 mph | about 4°F warmer on summer afternoons |
| Rancho San Antonio | 3.6 mi | +2°F | 16% | 9 mph | about 29% more rain a year |
| Half Moon Bay | 22.5 mi | -15°F | 64% | 8 mph | more summer morning fog (64% vs 16% of morning hours) and about 15°F cooler on summer afternoons |
| Año Nuevo State Park | 23.9 mi | -20°F | 42% | 14 mph | about 20°F cooler on summer afternoons and about 71% more rain a year |
| Año Nuevo Point | 24.5 mi | -20°F | 42% | 14 mph | about 20°F cooler on summer afternoons and about 71% more rain a year |
Places with a climate like Sunnyvale's
- Fremont (13 mi away): nearly the same temperatures every month
- Gilroy (36 mi away): nearly the same temperatures every month
- Union City (16 mi away): nearly the same temperatures every month
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the Sunnyvale climate comparisons mean
These cards compare recent conditions at Sunnyvale with the available local baseline. Temperature and year-to-date rainfall use long-term normals when available. Fog, sunshine, wind, and comfort use the matching recent or modeled baseline identified on each card.
Positive and negative differences describe how Sunnyvale departs from its own usual pattern. They should not be read as a direct comparison with another city or as a forecast beyond the period shown.
Sunnyvale weather by month
August is the warmest month at Sunnyvale, with an average high of 82°F. December is the coldest, with an average low of 40°F. February is the wettest month (3.8 in.), out of about 18.4 in. a year. Morning fog peaks in August, when fog or low cloud covers 18% of the hours from 6 to 10 AM. July has the clearest middays, with clouds covering about 10% of the sky from 11 AM to 3 PM.
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Sunnyvale are September, June, and July. The best hours are usually 10 AM to 1 PM in September, 10 AM to 1 PM in June, and 10 AM to 1 PM in July.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 60°F | 40°F | 3.6 in | 8 | 12% | 29% | 6 mph | 9.9 h | 61 |
| Feb | 63°F | 42°F | 3.8 in | 8 | 10% | 25% | 7 mph | 10.8 h | 64 |
| Mar | 67°F | 44°F | 2.9 in | 7 | 10% | 29% | 8 mph | 11.9 h | 68 |
| Apr | 70°F | 46°F | 1.3 in | 5 | 6% | 23% | 9 mph | 13.2 h | 78 |
| May | 74°F | 50°F | 0.6 in | 3 | 7% | 20% | 10 mph | 14.2 h | 81 |
| Jun | 80°F | 53°F | 0.1 in | 2 | 11% | 10% | 10 mph | 14.7 h | 88 |
| Jul | 82°F | 55°F | 0.0 in | 0 | 17% | 10% | 10 mph | 14.5 h | 88 |
| Aug | 82°F | 55°F | 0.0 in | 1 | 18% | 10% | 10 mph | 13.5 h | 87 |
| Sep | 81°F | 54°F | 0.1 in | 1 | 10% | 13% | 9 mph | 12.3 h | 90 |
| Oct | 76°F | 50°F | 0.8 in | 4 | 12% | 15% | 7 mph | 11.1 h | 84 |
| Nov | 66°F | 44°F | 1.8 in | 6 | 11% | 19% | 6 mph | 10.1 h | 77 |
| Dec | 59°F | 40°F | 3.5 in | 8 | 18% | 31% | 5 mph | 9.6 h | 60 |
Morning fog is the share of hours from 6 to 10 AM with fog or low cloud. Midday cloud is the average from 11 AM to 3 PM, and afternoon wind is the average from 1 to 5 PM. The highlighted rows are the most comfortable months.
What makes Sunnyvale's weather different
When the fog burns off
11 AMwhen August fog usually thins (23% foggy at 8 AM)
Fog or low cloud covers Sunnyvale in 23% of 8 AM hours in August, the foggiest month. It usually thins to a third of that by 11 AM. April mornings are the least foggy (6%).
When the wind picks up
1 PMwhen afternoon wind builds, February–October
From February through October, wind at Sunnyvale typically builds after 1 PM. In June it peaks around 4 PM, averaging 11 mph with 1% of those hours windy, while mornings average 3 mph.
Daylight
9.6–14.7 hof daylight, Dec to Jun
Days at Sunnyvale range from about 9.6 hours in December to 14.7 hours in June. In mid-June the sun sets around 8:29 PM, and in mid-December around 4:56 PM.
Seasons at Sunnyvale
- Warm seasonJun 26 – Sep 26 · highs 80°F+
The warm season lasts about 3.1 months, from Jun 26 to Sep 26, when the average high is 80°F or warmer. Highs peak around Aug 8 at about 82°F.
- Cool seasonNov 28 – Feb 25 · highs 64°F or lower
The cool season runs from Nov 28 to Feb 25, when the average high is 64°F or lower. The coldest nights come around Dec 8, with an average low near 40°F.
- Rainy seasonNov 21 – Mar 29 · 77% of the year's rain
The rainy season runs from Nov 21 to Mar 29, when a day has at least a 20% chance of measurable rain. That stretch brings 77% of the year's rain.
The dark line marks today. Season dates come from the smoothed daily NOAA 1991-2020 normals. Counting from Oct. 1, a typical year has its first inch of rain by Nov 5 and half of its annual total by Jan 27.
Days per year and extremes (Nov 1, 2024 to Oct 31, 2026)
This record runs from Nov 1, 2024 to Oct 31, 2026. Over this record, Sunnyvale averaged 7 days a year at 90°F or hotter and no freezing nights. It averaged 9 days a year with at least half an inch of rain and 1 afternoon with wind of 20 mph or more at 2 PM. About 54 mornings a year had 3 or more hours of fog or low cloud.
In the same record, the hottest day was Jun 11, 2026 (99°F) and the coldest night was Jan 28, 2025 (33°F). The wettest day was Feb 5, 2025 (1.34 in.), and the strongest 2 PM gust was 46 mph on Mar 12, 2025.
- 7days at 90°F or hotter
- 0nights at or below freezing
- 9days with ½ in. of rain or more
- 1afternoon with 20+ mph wind
- 54mornings with 3+ hours of fog or low cloud
- Hottest day99°FJun 11, 2026
- Coldest night33°FJan 28, 2025
- Wettest day1.34 inFeb 5, 2025
- Strongest 2 PM gust46 mphMar 12, 2025
What shapes Sunnyvale's weather
The Santa Cruz Mountains west of Sunnyvale block most coastal fog. On some summer nights low cloud still spreads over the valley. It can linger into late morning when the marine layer, the cool, damp ocean air beneath the fog, runs deep. Afternoons are reliably sunny. With no hills to shade or channel the air, temperatures are fairly even across the city.
Sunnyvale lies in the rain shadow of the Santa Cruz Mountains, the drier zone on their downwind side, and gets much less rain than the hills. Most of it falls from November through March. Fall offshore winds, which blow from the interior toward the coast, bring some of the year's hottest days. In winter, a clear, calm night after a rain can cool the damp ground enough for dense fog to form by morning.
Tips for visiting Sunnyvale
Visit the Baylands wetlands in the morning
Mornings, before the geese fly, are the best viewing time at Sunnyvale Baylands. Winds can get high later in the day.
Go in winter for waterfowl
Wetland water levels are high in winter, drawing ducks and geese. As the ponds dry in spring, shorebirds replace them.
Find shade in the park's south end
On hot summer days the lawns and trees in the south and central parts of Baylands Park are the cooler, shadier spots.
Take Caltrain downtown
Sunnyvale's Caltrain station at 121 W. Evelyn Avenue is a short walk from Murphy Avenue.
Check your flood zone before winter
Valley Water urges Santa Clara County residents to check their address against federal flood maps before the rainy season.
Sunnyvale through the seasons
- Spring (March–May)
- Wetlands dry out and shorebirds arrive at the Baylands. Warm, sunny afternoons return with a building breeze.
- Summer (June–August)
- Summer brings some overnight low cloud, then sunny, warm afternoons cooled by the sea breeze off the Bay. Rain is almost unheard of.
- Fall (September–November)
- Offshore winds, most common in fall, shut off the sea breeze and bring some of the hottest days of the year. September stays nearly as warm as August.
- Winter (December–February)
- Winter is mild and rainy, with cold, clear nights between storms. Geese and ducks fill the Baylands wetlands.
Activities and the weather that matters
- Birding at Sunnyvale Baylands: Birding works year-round, with waterfowl in winter and songbirds from spring through fall. Calm mornings beat windy afternoons.
- Kite flying and model planes: The big lawn at Baylands Park is used for kites and drones. The afternoon breeze helps kites but can be too strong for small aircraft.
- Evenings on Murphy Avenue: Outdoor dining is pleasant most of the year, best on warm summer evenings after the breeze settles.
Official sources and current conditions
- Santa Clara Valley Bird Alliance: Sunnyvale Baylands birding guide
- Caltrain: Sunnyvale station
- Valley Water: Flood Ready
Numbers on this page come from NOAA data. The text draws on the official sources linked above.
Historical Climate Data
Long-term weather patterns and climate data
Data sources: Recent temperatures come from NOAA URMA and recent precipitation from NOAA Stage IV. Fog, cloud, wind, humidity, and sunshine come from NOAA HRRR, and long-term baselines from NOAA 1991-2020 climate normals.
Climate Overview
Based on NOAA 30-year temperature/rain normals (1991-2020) with recent fog/sun baseline
🌟 Best Months to Visit
⚠️ Challenging Months
Monthly Breakdown
| Month | Comfort | High/Low | ☀️ Sun | 🌫️ Fog | 💧 Rain | Perfect |
|---|---|---|---|---|---|---|
| November 2024 | 83 | 63.9° / 45° | 6.4h | 1d | 1.75" | 21 |
| December 2024 | 77 | 61.9° / 44.5° | 5.5h | 7d | 2.67" | 14 |
| January 2025 | 86 | 60.9° / 39.9° | 7.1h | 2d | 0.05" | 23 |
| February 2025 | 80 | 62.8° / 43.9° | 6.8h | 2d | 4.06" | 17 |
| March 2025 | 87 | 63.9° / 45.7° | 8.6h | 2d | 1.61" | 24 |
| April 2025 | 92 | 68.8° / 48.5° | 9.7h | 0d | 0.41" | 26 |
| May 2025 | 96 | 75.2° / 52° | 12h | 0d | 0.04" | 31 |
| June 2025 | 95 | 74.7° / 54.4° | 12.5h | 0d | 0" | 30 |
| July 2025 | 93 | 76.1° / 58° | 11.5h | 2d | 0" | 31 |
| August 2025 | 92 | 80° / 59.1° | 10.6h | 5d | 0" | 30 |
| September 2025 | 92 | 79.5° / 61.7° | 9.5h | 3d | 0.15" | 29 |
| October 2025 | 90 | 73.2° / 53.5° | 8.1h | 4d | 1.42" | 27 |
| November 2025 | 80 | 65.3° / 49° | 6.5h | 10d | 2.65" | 17 |
| December 2025 | 73 | 59.3° / 45° | 5.2h | 11d | 2.35" | 7 |
| January 2026 | 83 | 62.8° / 42.8° | 6.7h | 3d | 2.51" | 23 |
| February 2026 | 81 | 64.9° / 46.2° | 6.8h | 4d | 3" | 21 |
| March 2026 | 95 | 77.1° / 51° | 9.8h | 0d | 0" | 30 |
| April 2026 | 90 | 69.3° / 50.3° | 9.2h | 0d | 1.81" | 25 |
| May 2026 | 93 | 73.1° / 53.6° | 11.3h | 3d | 0.28" | 30 |
| June 2026 | 95 | 78.4° / 57.4° | 12.1h | 0d | 0" | 29 |
| July 2026 | 94 | 78.7° / 58.5° | 11.7h | 0d | 0" | 31 |
| August 2026 | 93 | 78.2° / 59.6° | 10.7h | 5d | 0" | 30 |
| September 2026 | 95 | 78.8° / 56.8° | 10.1h | 1d | 0.04" | 30 |
| October 2026 | 91 | 76.1° / 53.1° | 8.1h | 3d | 0.09" | 29 |
Climate Trends
Average Temperature by Month
About the Sunnyvale climate charts
The temperature chart compares average monthly highs and lows at Sunnyvale, showing both the seasonal cycle and the typical day-to-night range. The comfort chart summarizes how often the combined weather pattern is favorable rather than judging temperature alone.
Precipitation shows the total recorded or modeled rainfall for each month at Sunnyvale. Sunshine compares average bright-sky hours with the daylight available, while fog shows the average number of morning fog or low-cloud hours per day. Switch between the chart tabs to compare the same months across each measure.
Hourly Temperature, Fog, Wind, Cloud Cover, and Solar Radiation Patterns
Average local hour by month from 2014-09-30 to 2026-04-30
- Temperature: At Sunnyvale, the warmest typical hour is 3 PM in August (80°F). The coldest is 7 AM in January (44°F).
- Fog: Fog or low cloud covers Sunnyvale in 23% of 8 AM hours in August, the foggiest month. It usually thins to a third of that by 11 AM. April mornings are the least foggy (6%).
- Wind: From February through October, wind at Sunnyvale typically builds after 1 PM. In June it peaks around 4 PM, averaging 11 mph with 1% of those hours windy, while mornings average 3 mph.
- Cloud Cover: July middays are the clearest at Sunnyvale (10% average cloud cover), and December middays are the cloudiest (31%).
- Solar Radiation: The strongest typical sun at Sunnyvale comes at 1 PM in June, averaging 988 W/m².
How to read the hourly heatmaps for Sunnyvale
This heatmap shows how average temperature at Sunnyvale changes by hour and month. Read left to right for the seasons and top to bottom for the time of day. Warmer colors mark the usual afternoon peaks, and cooler colors show overnight and winter lows.
This heatmap shows when fog or low cloud is most likely at Sunnyvale. Darker cells mark the months and hours when fog has been most common. They help separate overnight or morning fog from cloud that tends to linger into the afternoon.
This heatmap shows the typical hourly wind pattern at Sunnyvale through the year. It makes recurring afternoon wind, calmer overnight periods, and seasonal changes easier to compare than a single daily wind value.
This heatmap shows average cloud cover at Sunnyvale for every month and hour. Use it to see whether cloudiness is mainly an overnight and morning pattern or commonly persists during the part of the day you plan to visit.
This heatmap shows the average solar radiation reaching Sunnyvale by month and hour. Brighter cells indicate the strongest typical sun, while muted cells can reflect nighttime, shorter winter days, cloud cover, smoke, or terrain shading.
Each cell combines one month with one local hour. Hover over or focus on a cell for its value and sample coverage. The red marker shows the current month and hour.
How recent months compared at Sunnyvale
- October 2026 recap: October 2026 at Sunnyvale averaged a high of 76°F, 3°F warmer than October 2025 (73°F).
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 14.1 in. of rain to Sunnyvale, 76% of the 18.4 in. normal.
Location Details
Sunnyvale weather questions
Everything you need to know about weather and visiting Sunnyvale
What is the weather like at Sunnyvale today?
It's 53°F at Sunnyvale right now, with a comfort score of 77 (great). Monday's forecast high at Sunnyvale is 56°F, 10°F below the mid November normal of 66°F. The best window today is 10 AM to 1 PM, at about 54°F with a 3 mph wind (comfort 62).
What is the best month to visit Sunnyvale?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Sunnyvale are September, June, and July. The best hours are usually 10 AM to 1 PM in September, 10 AM to 1 PM in June, and 10 AM to 1 PM in July. The warm season lasts about 3.1 months, from Jun 26 to Sep 26, when the average high is 80°F or warmer. Highs peak around Aug 8 at about 82°F.
What are the warmest and coldest months at Sunnyvale?
August is the warmest month at Sunnyvale, with an average high of 82°F. December is the coldest, with an average low of 40°F.
When does the fog burn off at Sunnyvale?
Fog or low cloud covers Sunnyvale in 23% of 8 AM hours in August, the foggiest month. It usually thins to a third of that by 11 AM. April mornings are the least foggy (6%).
When is it windiest at Sunnyvale?
From February through October, wind at Sunnyvale typically builds after 1 PM. In June it peaks around 4 PM, averaging 11 mph with 1% of those hours windy, while mornings average 3 mph.
How much rain does Sunnyvale get?
February is the wettest month (3.8 in.), out of about 18.4 in. a year. The rainy season runs from Nov 21 to Mar 29, when a day has at least a 20% chance of measurable rain. That stretch brings 77% of the year's rain. The 2025-26 rain year (Oct. 1 to Sep. 30) brought 14.1 in. of rain to Sunnyvale, 76% of the 18.4 in. normal.
What kind of place is Sunnyvale?
Sunnyvale spreads across the open floor of the Santa Clara Valley. Its grid of neighborhoods and tech campuses runs from the El Camino Real corridor north to the Bay's salt ponds and Moffett Field. Its Murphy Avenue downtown sits beside the Caltrain station on Evelyn Avenue. At the Bay edge, Sunnyvale Baylands Park pairs lawns and picnic groves with more than a hundred acres of restored seasonal wetlands. Reclaimed water from the city's water pollution control plant keeps them wet.
What is Sunnyvale weather like in November?
November at Sunnyvale averages a high of 66°F and a low of 44°F, with 1.8 in. of rain over about 6 rainy days. About 11% of morning hours are foggy. Afternoon wind averages 6 mph.
More about Sunnyvale weather
Guides that explain the weather here and nearby
Data sources and methods
- Monthly temperatures and precipitation: NOAA 1991-2020 normals.
- Fog, cloud, wind, sun, and comfort by hour and month: NOAA's HRRR hourly analysis from September 2014 to April 2026.
- Daily records and recent months: NOAA URMA and HRRR analyses, plus NOAA Stage IV precipitation.
- Nearby comparisons and regional rankings use the same hourly HRRR summaries for every destination in the region.
- Alerts: National Weather Service. Tides and ocean temperature: NOAA CO-OPS, where shown.
- All statements on this page are computed from these datasets, apart from the “What shapes the weather” guide, which cites its sources inline.
- Santa Clara Valley Bird Alliance, Sunnyvale Baylands Park self-guided birding (accessed 2026-10-27)
- Caltrain, Sunnyvale station (accessed 2026-10-27)
- Valley Water, Flood Ready (accessed 2026-10-27)
- National Weather Service, Climate of San Jose (NOAA Technical Memorandum NWS WR-259) (accessed 2026-10-27)
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