Walnut Creek Weather
Town • San Francisco Bay Area
Central Contra Costa County's business and arts center, Walnut Creek sits in the Diablo Valley where the I-680 and Highway 24 corridors meet below Mount Diablo. Its downtown grew up around the BART station, and its eastern edge climbs straight into protected hills. Diablo Foothills Regional Park and the city's own open space form the western gateway to Mount Diablo State Park, whose North Gate road starts in town. The paved Contra Costa Canal Trail loops through on its way between Martinez and Concord.
Plan your week
10-Day Forecast
Hour by hour
Hourly Forecast
Current Conditions
Comfort Breakdown
Walnut Creek weather today and through the year
It's 54°F at Walnut Creek right now (feels like 51°F), with 5 mph wind and a comfort score of 78. Monday's forecast high at Walnut Creek is 57°F, 8°F below the mid November normal of 65°F. The best window today is 8 AM to 11 AM, at about 55°F with a 6 mph wind (comfort 58).
July is the warmest month at Walnut Creek, with an average high of 86°F. December is the coldest, with an average low of 39°F. January is the wettest month (4.0 in.), out of about 19.7 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Walnut Creek are June, September, and October. The best hours are usually 10 AM to 1 PM in June, 9 AM to noon in September, and 11 AM to 2 PM in October.
Walnut Creek is on the dry side of the Coast Range. The Berkeley Hills, Briones, and Las Trampas ridges stand between it and the bay. The Bay Area Air District notes that the Coast Range blocks marine air from the Diablo and San Ramon valleys. That is why summer afternoons here run hot while Oakland, less than 20 miles west, stays mild and often gray.
Forecast updated November 15, 2026 at 3:01 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 Walnut Creek in the next few days
No active National Weather Service alerts for this location.
Best time to go
The best window today is 8 AM to 11 AM, at about 55°F with a 6 mph wind (comfort 58).
Best day this week
Of the next 7 days, Friday looks best for Walnut Creek, with a 60°F high and midday comfort near 78. Today looks weakest (56).
Rain
Next good chance of rain: today (75%, about 0.15 in.).
Live weather map
Weather around Walnut Creek right now
Overcast and 54° at Walnut Creek right now.
About the live weather map for Walnut Creek
The map centers on Walnut Creek 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.
Walnut Creek vs nearby places
Typical summer conditions compared with Walnut Creek, 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 Walnut Creek |
|---|---|---|---|---|---|
| Pleasant Hill | 2.6 mi | +1°F | 10% | 7 mph | a very similar climate |
| Lafayette | 3.3 mi | -2°F | 13% | 9 mph | a very similar climate |
| Briones Regional Park | 4.5 mi | -7°F | 23% | 11 mph | about 7°F cooler on summer afternoons and about 42% more rain a year |
| Crissy Field | 23 mi | -26°F | 40% | 18 mph | about 26°F cooler on summer afternoons and windier summer afternoons (18 vs 8 mph) |
| Presidio of San Francisco | 23.2 mi | -26°F | 40% | 18 mph | about 26°F cooler on summer afternoons and windier summer afternoons (18 vs 8 mph) |
| Baker Beach | 24.2 mi | -27°F | 45% | 16 mph | about 27°F cooler on summer afternoons and more summer morning fog (45% vs 11% of morning hours) |
Places with a climate like Walnut Creek's
- Evergreen (45 mi away): nearly the same temperatures every month
- Dublin (16 mi away): nearly the same temperatures every month
- Pleasanton (20 mi away): nearly the same temperatures every month
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the Walnut Creek climate comparisons mean
These cards compare recent conditions at Walnut Creek 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 Walnut Creek 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.
Walnut Creek weather by month
July is the warmest month at Walnut Creek, with an average high of 86°F. December is the coldest, with an average low of 39°F. January is the wettest month (4.0 in.), out of about 19.7 in. a year. Morning fog peaks in December, when fog or low cloud covers 24% of the hours from 6 to 10 AM. July has the clearest middays, with clouds covering about 5% of the sky from 11 AM to 3 PM.
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Walnut Creek are June, September, and October. The best hours are usually 10 AM to 1 PM in June, 9 AM to noon in September, and 11 AM to 2 PM in October.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 56°F | 39°F | 4.0 in | 8 | 21% | 35% | 6 mph | 9.8 h | 58 |
| Feb | 62°F | 42°F | 3.8 in | 8 | 10% | 24% | 7 mph | 10.7 h | 63 |
| Mar | 66°F | 44°F | 3.0 in | 7 | 6% | 28% | 8 mph | 11.9 h | 68 |
| Apr | 70°F | 46°F | 1.4 in | 5 | 4% | 20% | 8 mph | 13.2 h | 80 |
| May | 76°F | 50°F | 0.6 in | 3 | 7% | 16% | 9 mph | 14.2 h | 83 |
| Jun | 83°F | 54°F | 0.1 in | 2 | 11% | 6% | 9 mph | 14.8 h | 88 |
| Jul | 86°F | 56°F | 0.0 in | 0 | 13% | 5% | 8 mph | 14.5 h | 85 |
| Aug | 86°F | 56°F | 0.0 in | 1 | 8% | 6% | 8 mph | 13.6 h | 85 |
| Sep | 84°F | 54°F | 0.1 in | 1 | 5% | 10% | 7 mph | 12.3 h | 87 |
| Oct | 77°F | 50°F | 0.9 in | 4 | 4% | 14% | 6 mph | 11.1 h | 86 |
| Nov | 65°F | 44°F | 1.9 in | 6 | 11% | 24% | 6 mph | 10.0 h | 77 |
| Dec | 57°F | 39°F | 4.0 in | 8 | 24% | 39% | 6 mph | 9.5 h | 56 |
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 Walnut Creek's weather different
When the fog burns off
4 PMwhen December fog usually thins (26% foggy at 8 AM)
Fog or low cloud covers Walnut Creek in 26% of 8 AM hours in December, the foggiest month. It usually thins to a third of that by 4 PM. April mornings are the least foggy (4%).
When the wind picks up
2 PMwhen afternoon wind builds, March–September
From March through September, wind at Walnut Creek typically builds after 2 PM. In May it peaks around 5 PM, averaging 11 mph with 5% of those hours windy, while mornings average 7 mph.
Hot hours
2 habove 85°F on a typical July afternoon
In July, the average temperature stays at or above 85°F for 2 hours a day.
Microclimate
−7°FBriones Regional Park, 4.5 mi away, on summer afternoons
Briones Regional Park, 4.5 miles away, runs about 7°F cooler than Walnut Creek on summer afternoons. It also has more summer morning fog, 23% of morning hours compared with 11%.
Daylight
9.5–14.8 hof daylight, Dec to Jun
Days at Walnut Creek range from about 9.5 hours in December to 14.8 hours in June. In mid-June the sun sets around 8:32 PM, and in mid-December around 4:53 PM.
Seasons at Walnut Creek
- Warm seasonJun 25 – Sep 25 · highs 83°F+
The warm season lasts about 3.1 months, from Jun 25 to Sep 25, when the average high is 83°F or warmer. Highs peak around Jul 8 at about 86°F.
- Hot afternoonsJul 3 – Sep 3 · highs 85°F+
Average highs reach 85°F or more from Jul 3 to Sep 3.
- Cool seasonNov 27 – Feb 26 · highs 63°F or lower
The cool season runs from Nov 27 to Feb 26, when the average high is 63°F or lower. The coldest nights come around Dec 8, with an average low near 39°F.
- Rainy seasonNov 19 – Mar 29 · 77% of the year's rain
The rainy season runs from Nov 19 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 2 and half of its annual total by Jan 24.
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, Walnut Creek averaged 40 days a year at 90°F or hotter and no freezing nights. It averaged 17 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 52 mornings a year had 3 or more hours of fog or low cloud.
In the same record, the hottest day was Aug 3, 2026 (103°F) and the coldest night was Feb 10, 2025 (33°F). The wettest day was Nov 23, 2024 (2.12 in.), and the strongest 2 PM gust was 41 mph on Mar 12, 2025.
- 40days at 90°F or hotter
- 0nights at or below freezing
- 17days with ½ in. of rain or more
- 1afternoon with 20+ mph wind
- 52mornings with 3+ hours of fog or low cloud
- Hottest day103°FAug 3, 2026
- Coldest night33°FFeb 10, 2025
- Wettest day2.12 inNov 23, 2024
- Strongest 2 PM gust41 mphMar 12, 2025
What shapes Walnut Creek's weather
Walnut Creek's distance from the water means bigger swings between day and night. The Air District describes these valleys as warm in summer and cool in winter, with generally light wind. On clear, still nights cool air drains off Mount Diablo and the Shell Ridge foothills and settles on the valley floor. Winter mornings can dip close to freezing after mild afternoons. Tule fog, the dense ground fog of calm, cold nights, is common at night in winter.
The main source of summer relief in central Contra Costa is the marine air that pushes east through the Carquinez Strait. The Air District says strong afternoon gusts are common in the strait. Walnut Creek sits well south of the strait, so it gets less of that breeze than Martinez or Concord, and hot afternoons often fade only after sunset.
Heat and still air also shape air quality. Ozone, a lung irritant that forms in strong sunlight, is mainly a summer problem in the county. The haze that builds over the valley on hot days is why views from Mount Diablo are usually sharpest after a winter storm.
Tips for visiting Walnut Creek
Take BART downtown
Walnut Creek BART is at 200 Ygnacio Valley Road. BART-purchased parking is valid in the North Garage but not in the privately run South Garage.
Drive up Mount Diablo from North Gate
The North Gate Road entrance is in Walnut Creek. Park gates open at 8 a.m. and close at sunset.
Carry more water than you think
State Parks advises drinking at least a quart of water every two hours when hiking on Mount Diablo, and summer heat in the foothills makes that a minimum.
Castle Rock closes for nesting falcons
In Diablo Foothills Regional Park, the Castle Rock formations close from February 1 to August 1 each year to protect nesting peregrine falcons.
Use the canal trail for a flat ride
The paved Contra Costa Canal Trail connects Martinez, Pleasant Hill, Walnut Creek, and Concord. Swimming and fishing in the canal are not allowed.
Walnut Creek through the seasons
- Spring (March–May)
- Spring brings green foothills and some of the best hiking weather of the year. Castle Rock's formations stay closed for nesting falcons until August 1.
- Summer (June–August)
- Summer afternoons are hot and dry, with light wind. State Parks notes that summer visibility from Mount Diablo is often hazy.
- Fall (September–October)
- Heat lingers through September, and the dry grass on the hills keeps fire danger high until rain arrives. Weather conditions can close Mount Diablo during extreme fire danger.
- Winter (November–February)
- Winter mornings are cool and can dip close to freezing, and tule fog forms on some nights. State Parks says the best Mount Diablo views often come the day after a winter storm.
Activities and the weather that matters
- Hiking the foothills: Spring and the cooler hours of fall are ideal. Summer afternoons on the exposed grassland are hot, so start early.
- Driving to Mount Diablo's summit: Clear days after winter storms give the longest views. State Parks says that on the best days you can see almost 200 miles.
- Biking the Contra Costa Canal Trail: Paved and mostly flat, it suits mornings in summer and almost any dry day from fall through spring.
Official sources and current conditions
- California State Parks: Mount Diablo State Park
- East Bay Regional Park District: Diablo Foothills
- BART: Walnut Creek station
- Bay Area Air District: Contra Costa County air quality
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 | 82 | 63.4° / 45.7° | 6.4h | 1d | 3.56" | 21 |
| December 2024 | 69 | 58.3° / 44.8° | 4.7h | 10d | 5.86" | 10 |
| January 2025 | 84 | 60° / 40.3° | 7h | 2d | 0.2" | 24 |
| February 2025 | 77 | 61.8° / 43.6° | 6.6h | 4d | 7.07" | 18 |
| March 2025 | 86 | 63.7° / 45.7° | 8.6h | 0d | 2.83" | 22 |
| April 2025 | 94 | 70.8° / 48.8° | 9.9h | 0d | 0.37" | 29 |
| May 2025 | 94 | 77.9° / 53.2° | 12.4h | 0d | 0.31" | 30 |
| June 2025 | 95 | 80.7° / 54.6° | 12.7h | 1d | 0" | 30 |
| July 2025 | 92 | 80.9° / 57° | 12.3h | 3d | 0" | 29 |
| August 2025 | 89 | 88.3° / 59.6° | 11.5h | 1d | 0" | 26 |
| September 2025 | 91 | 83.4° / 61.7° | 9.7h | 0d | 0.09" | 27 |
| October 2025 | 90 | 74.3° / 53.7° | 8h | 0d | 1.72" | 28 |
| November 2025 | 78 | 64.2° / 49.8° | 5.9h | 10d | 3.23" | 18 |
| December 2025 | 62 | 54.8° / 44.9° | 3.9h | 19d | 4.68" | 3 |
| January 2026 | 73 | 59.7° / 43.6° | 6.3h | 14d | 3.79" | 13 |
| February 2026 | 79 | 64.4° / 45.6° | 6.4h | 5d | 4.99" | 19 |
| March 2026 | 95 | 78.9° / 52.3° | 9.8h | 0d | 0.04" | 31 |
| April 2026 | 89 | 69.6° / 50.1° | 9.3h | 1d | 4.48" | 22 |
| May 2026 | 95 | 75.9° / 53.8° | 11.7h | 0d | 0.56" | 30 |
| June 2026 | 94 | 81.5° / 56.9° | 12.6h | 4d | 0" | 29 |
| July 2026 | 93 | 85.5° / 59° | 11.6h | 1d | 0" | 29 |
| August 2026 | 92 | 87.4° / 59.5° | 11.3h | 0d | 0" | 29 |
| September 2026 | 93 | 82.1° / 57.7° | 10.4h | 0d | 0.76" | 28 |
| October 2026 | 88 | 79.5° / 54.7° | 8.2h | 2d | 0.39" | 24 |
Climate Trends
Average Temperature by Month
About the Walnut Creek climate charts
The temperature chart compares average monthly highs and lows at Walnut Creek, 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 Walnut Creek. 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 Walnut Creek, the warmest typical hour is 3 PM in August (86°F). The coldest is 7 AM in December (44°F).
- Fog: Fog or low cloud covers Walnut Creek in 26% of 8 AM hours in December, the foggiest month. It usually thins to a third of that by 4 PM. April mornings are the least foggy (4%).
- Wind: From March through September, wind at Walnut Creek typically builds after 2 PM. In May it peaks around 5 PM, averaging 11 mph with 5% of those hours windy, while mornings average 7 mph.
- Cloud Cover: July middays are the clearest at Walnut Creek (5% average cloud cover), and December middays are the cloudiest (39%).
- Solar Radiation: The strongest typical sun at Walnut Creek comes at 1 PM in June, averaging 1000 W/m².
How to read the hourly heatmaps for Walnut Creek
This heatmap shows how average temperature at Walnut Creek 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 Walnut Creek. 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 Walnut Creek 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 Walnut Creek 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 Walnut Creek 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 Walnut Creek
- October 2026 recap: October 2026 at Walnut Creek averaged a high of 80°F, 3°F warmer than the 1991-2020 normal of 77°F. It brought 0.39 in. of rain, compared with a normal of 0.91 in.
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 24.3 in. of rain to Walnut Creek, 123% of the 19.7 in. normal.
Location Details
Walnut Creek weather questions
Everything you need to know about weather and visiting Walnut Creek
What is the weather like at Walnut Creek today?
It's 54°F at Walnut Creek right now, with a comfort score of 78 (great). Monday's forecast high at Walnut Creek is 57°F, 8°F below the mid November normal of 65°F. The best window today is 8 AM to 11 AM, at about 55°F with a 6 mph wind (comfort 58).
What is the best month to visit Walnut Creek?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Walnut Creek are June, September, and October. The best hours are usually 10 AM to 1 PM in June, 9 AM to noon in September, and 11 AM to 2 PM in October. The warm season lasts about 3.1 months, from Jun 25 to Sep 25, when the average high is 83°F or warmer. Highs peak around Jul 8 at about 86°F.
What are the warmest and coldest months at Walnut Creek?
July is the warmest month at Walnut Creek, with an average high of 86°F. December is the coldest, with an average low of 39°F.
When does the fog burn off at Walnut Creek?
Fog or low cloud covers Walnut Creek in 26% of 8 AM hours in December, the foggiest month. It usually thins to a third of that by 4 PM. April mornings are the least foggy (4%).
When is it windiest at Walnut Creek?
From March through September, wind at Walnut Creek typically builds after 2 PM. In May it peaks around 5 PM, averaging 11 mph with 5% of those hours windy, while mornings average 7 mph.
How much rain does Walnut Creek get?
January is the wettest month (4.0 in.), out of about 19.7 in. a year. The rainy season runs from Nov 19 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 24.3 in. of rain to Walnut Creek, 123% of the 19.7 in. normal.
How does Walnut Creek weather compare with Briones Regional Park?
Briones Regional Park, 4.5 miles away, runs about 7°F cooler than Walnut Creek on summer afternoons. It also has more summer morning fog, 23% of morning hours compared with 11%.
What kind of place is Walnut Creek?
Central Contra Costa County's business and arts center, Walnut Creek sits in the Diablo Valley where the I-680 and Highway 24 corridors meet below Mount Diablo. Its downtown grew up around the BART station, and its eastern edge climbs straight into protected hills. Diablo Foothills Regional Park and the city's own open space form the western gateway to Mount Diablo State Park, whose North Gate road starts in town. The paved Contra Costa Canal Trail loops through on its way between Martinez and Concord.
What is Walnut Creek weather like in November?
November at Walnut Creek averages a high of 65°F and a low of 44°F, with 1.9 in. of rain over about 6 rainy days. About 11% of morning hours are foggy. Afternoon wind averages 6 mph.
More about Walnut Creek weather
Guides that explain the weather here and nearby
- Walnut Creek Weather: Diablo Valley Heat and Sunshine
- Why the Bay Area Has So Many Microclimates
- Bay Area Coastal vs. Inland: 30-Degree Temperature Differences
- Bay Area Indian Summer: Why Fall Brings Heat, Not Cool
- Why Bay Area Fog Is Most Intense in Summer (Not Winter)
- San Francisco Weather in July: Fog and Cool Summer Days
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.
- BART, Walnut Creek station (accessed 2026-10-27)
- California State Parks, Mount Diablo State Park (accessed 2026-10-27)
- East Bay Regional Park District, Diablo Foothills Regional Park (accessed 2026-10-27)
- East Bay Regional Park District, Contra Costa Canal Regional Trail (accessed 2026-10-27)
Rendered 2026-11-15T11:50:54.872Z.