San Carlos Weather
Town • San Francisco Bay Area
San Carlos, the self-styled City of Good Living, is a compact mid-Peninsula town between Belmont and Redwood City. It is built around a walkable Laurel Street downtown, one block west of El Camino Real and the Caltrain station. Behind it the hills rise toward Pulgas Ridge, where Big Canyon and Eaton parks hold more than 73 acres of natural open space with trails. On the bay side of Highway 101, San Carlos Airport sits at the end of the Steinberger Slough levee, beside the marshes.
Plan your week
10-Day Forecast
Hour by hour
Hourly Forecast
Current Conditions
Comfort Breakdown
San Carlos weather today and through the year
It's 52°F at San Carlos right now (feels like 50°F), with 5 mph wind and a comfort score of 76. Monday's forecast high at San Carlos is 57°F, 7°F below the mid November normal of 64°F. The best window today is noon to 3 PM, at about 53°F with a 2 mph wind (comfort 59).
September is the warmest month at San Carlos, with an average high of 76°F. December is the coldest, with an average low of 42°F. January is the wettest month (4.0 in.), out of about 19.8 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at San Carlos are September, June, and July. The best hours are usually 10 AM to 1 PM in September, 11 AM to 2 PM in June, and 11 AM to 2 PM in July.
San Carlos is where the mid-Peninsula's warmth starts to show. The Santa Cruz Mountains to the west are higher and more continuous here than behind San Mateo, so less summer marine air spills over the crest. The cool afternoon wind that funnels down the bay from the San Bruno Gap has also lost some strength by the time it gets this far south. The result is a town that is usually sunnier and calmer than San Mateo on a summer afternoon, and much like Redwood City.
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 San Carlos in the next few days
No active National Weather Service alerts for this location.
Best time to go
The best window today is noon to 3 PM, at about 53°F with a 2 mph wind (comfort 59).
Best day this week
Of the next 7 days, Friday looks best for San Carlos, with a 61°F high and midday comfort near 79. Thursday looks weakest (51).
Rain
Next good chance of rain: today (79%, about 0.23 in.).
Live weather map
Weather around San Carlos right now
Overcast and 52° at San Carlos right now.
About the live weather map for San Carlos
The map centers on San Carlos 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.
San Carlos vs nearby places
Typical summer conditions compared with San Carlos, 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 San Carlos |
|---|---|---|---|---|---|
| Belmont | 1.2 mi | -1°F | 13% | 12 mph | a very similar climate |
| Redwood City | 2 mi | +2°F | 13% | 10 mph | a very similar climate |
| Edgewood Park & Natural Preserve | 3.4 mi | +2°F | 23% | 8 mph | more summer morning fog (23% vs 7% of morning hours) |
| Half Moon Bay | 9.7 mi | -13°F | 64% | 8 mph | more summer morning fog (64% vs 7% of morning hours) and about 13°F cooler on summer afternoons |
| Moss Beach | 13.9 mi | -18°F | 66% | 9 mph | more summer morning fog (66% vs 7% of morning hours) and about 18°F cooler on summer afternoons |
| Montara | 14.2 mi | -20°F | 60% | 8 mph | more summer morning fog (60% vs 7% of morning hours) and about 20°F cooler on summer afternoons |
Places with a climate like San Carlos'
- Vallejo (41 mi away): similar temperatures through the year
- San Anselmo (36 mi away): similar temperatures through the year
- Ross (35 mi away): similar temperatures through the year
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the San Carlos climate comparisons mean
These cards compare recent conditions at San Carlos 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 San Carlos 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.
San Carlos weather by month
September is the warmest month at San Carlos, with an average high of 76°F. December is the coldest, with an average low of 42°F. January is the wettest month (4.0 in.), out of about 19.8 in. a year. Morning fog peaks in December, when fog or low cloud covers 17% of the hours from 6 to 10 AM. June has the clearest middays, with clouds covering about 19% of the sky from 11 AM to 3 PM.
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at San Carlos are September, June, and July. The best hours are usually 10 AM to 1 PM in September, 11 AM to 2 PM in June, and 11 AM to 2 PM in July.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 59°F | 42°F | 4.0 in | 8 | 11% | 35% | 5 mph | 9.9 h | 60 |
| Feb | 61°F | 44°F | 3.9 in | 8 | 10% | 28% | 7 mph | 10.8 h | 62 |
| Mar | 64°F | 46°F | 3.0 in | 7 | 8% | 32% | 8 mph | 11.9 h | 66 |
| Apr | 66°F | 47°F | 1.4 in | 5 | 6% | 27% | 9 mph | 13.2 h | 75 |
| May | 69°F | 51°F | 0.6 in | 3 | 5% | 29% | 10 mph | 14.2 h | 77 |
| Jun | 73°F | 53°F | 0.1 in | 2 | 5% | 19% | 10 mph | 14.7 h | 87 |
| Jul | 75°F | 55°F | 0.0 in | 0 | 8% | 20% | 10 mph | 14.5 h | 87 |
| Aug | 75°F | 55°F | 0.0 in | 1 | 9% | 21% | 10 mph | 13.6 h | 87 |
| Sep | 76°F | 54°F | 0.1 in | 1 | 7% | 22% | 9 mph | 12.3 h | 89 |
| Oct | 73°F | 51°F | 0.9 in | 4 | 10% | 21% | 7 mph | 11.1 h | 83 |
| Nov | 64°F | 46°F | 1.9 in | 6 | 10% | 24% | 5 mph | 10.1 h | 76 |
| Dec | 59°F | 42°F | 3.9 in | 8 | 17% | 35% | 5 mph | 9.6 h | 59 |
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 San Carlos' weather different
When the fog burns off
noonwhen December fog usually thins (19% foggy at 7 AM)
Fog or low cloud covers San Carlos in 19% of 7 AM hours in December, the foggiest month. It usually thins to a third of that by noon. May mornings are the least foggy (5%).
When the wind picks up
1 PMwhen afternoon wind builds, February–October
From February through October, wind at San Carlos typically builds after 1 PM. In May it peaks around 5 PM, averaging 12 mph with 10% of those hours windy, while mornings average 4 mph.
Microclimate
−13°FHalf Moon Bay, 9.7 mi away, on summer afternoons
Half Moon Bay, 9.7 miles away, runs about 13°F cooler than San Carlos on summer afternoons. It also has far more summer morning fog, 64% of morning hours compared with 7%.
Daylight
9.6–14.7 hof daylight, Dec to Jun
Days at San Carlos range from about 9.6 hours in December to 14.7 hours in June. In mid-June the sun sets around 8:30 PM, and in mid-December around 4:57 PM.
Seasons at San Carlos
- Warm seasonJul 1 – Sep 30 · highs 74°F+
The warm season lasts about 3 months, from Jul 1 to Sep 30, when the average high is 74°F or warmer. Highs peak around Sep 8 at about 76°F.
- Cool seasonNov 27 – Mar 2 · highs 63°F or lower
The cool season runs from Nov 27 to Mar 2, when the average high is 63°F or lower. The coldest nights come around Dec 8, with an average low near 42°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 26.
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, San Carlos averaged 13 days a year at 90°F or hotter and no freezing nights. It averaged 12 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 36 mornings a year had 3 or more hours of fog or low cloud.
In the same record, the hottest day was Sep 9, 2026 (99°F) and the coldest night was Jan 27, 2025 (37°F). The wettest day was Nov 23, 2024 (1.96 in.), and the strongest 2 PM gust was 44 mph on Mar 12, 2025.
- 13days at 90°F or hotter
- 0nights at or below freezing
- 12days with ½ in. of rain or more
- 1afternoon with 20+ mph wind
- 36mornings with 3+ hours of fog or low cloud
- Hottest day99°FSep 9, 2026
- Coldest night37°FJan 27, 2025
- Wettest day1.96 inNov 23, 2024
- Strongest 2 PM gust44 mphMar 12, 2025
What shapes San Carlos' weather
Inside San Carlos, the split is between the flats and the canyons. Laurel Street and the neighborhoods around El Camino Real are level and sheltered. Big Canyon and the hillside streets climb toward the ridge above the Crystal Springs valley. They pick up more breeze, plus cooler, damper air on foggy evenings.
San Carlos's bay side has its own weather. Out by the airport and the Steinberger Slough marshes, the afternoon breeze blows freely across flat, open ground. A walk there can feel a season cooler than lunch on Laurel Street the same day.
Tips for visiting San Carlos
Take Caltrain to downtown
San Carlos station is at 599 El Camino Real, with bike racks, BikeLink e-lockers, and SamTrans connections.
Hike Big Canyon and Eaton early
The two hillside parks hold more than 73 acres of open space on exposed slopes. Mornings beat the afternoon heat there.
Walk the levee at low tide
A gravel levee trail follows Steinberger Slough to San Carlos Airport. At low tide the slough turns to mudflats used by shorebirds.
Use the trailhead map kiosks
Big Canyon and Eaton Parks have entrance kiosks with trail maps, so check them before setting out. To report a trail hazard, call Parks & Recreation at (650) 802-4109.
San Carlos through the seasons
- Spring (March–May)
- Spring brings green hills and mild afternoons, the best season for the Big Canyon and Eaton trails.
- Summer (June–August)
- Summer is mostly sunny and warm downtown while fog stays on the coast side of the ridge. The bayfront and hilltops get the wind.
- Fall (September–October)
- September typically brings the warmest weeks of the year, when the sea breeze fades and the hillside grass is at its driest.
- Winter (November–February)
- Winter is the rainy season. Hillside trails get muddy, and clear nights between storms are cold in the canyon bottoms.
Activities and the weather that matters
- Hillside hiking: Big Canyon and Eaton parks are best on mild spring days and cool mornings. Summer afternoons on the open slopes run warm.
- Laurel Street dining: Laurel Street is sheltered from the bay wind, so outdoor tables work on most dry evenings from spring through fall.
- Shorebird watching: Go at low tide, when Steinberger Slough empties to mudflats. Calm mornings beat windy afternoons.
Official sources and current conditions
- City of San Carlos: trails
- City of San Carlos: about San Carlos
- Caltrain: San Carlos station
- San Francisco Bay Trail: Redwood Shores to Ravenswood Slough
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 | 84 | 63.9° / 47.4° | 6.5h | 2d | 3.07" | 23 |
| December 2024 | 74 | 61.3° / 46.7° | 5.1h | 6d | 4.64" | 13 |
| January 2025 | 85 | 61° / 43° | 6.7h | 1d | 0.13" | 23 |
| February 2025 | 78 | 62.3° / 45.6° | 6.6h | 3d | 5.81" | 17 |
| March 2025 | 85 | 63.7° / 47.1° | 8.1h | 0d | 1.9" | 23 |
| April 2025 | 92 | 68.4° / 49.1° | 9.5h | 0d | 0.42" | 27 |
| May 2025 | 96 | 73.8° / 52° | 12.1h | 0d | 0.15" | 31 |
| June 2025 | 96 | 74.5° / 53.9° | 12.4h | 0d | 0" | 30 |
| July 2025 | 95 | 75.9° / 57° | 11.4h | 1d | 0" | 31 |
| August 2025 | 94 | 81.3° / 58.6° | 11.1h | 0d | 0" | 31 |
| September 2025 | 91 | 80.1° / 61.2° | 9.3h | 0d | 0.13" | 29 |
| October 2025 | 91 | 73.4° / 54.8° | 8h | 1d | 0.54" | 29 |
| November 2025 | 81 | 65.9° / 50.9° | 6.3h | 6d | 2.45" | 17 |
| December 2025 | 72 | 58.9° / 46.7° | 5.1h | 10d | 3.44" | 11 |
| January 2026 | 82 | 62.6° / 45.6° | 6.8h | 3d | 4.15" | 24 |
| February 2026 | 82 | 64.5° / 48° | 6.9h | 3d | 2.24" | 21 |
| March 2026 | 95 | 77.8° / 52.8° | 9.6h | 1d | 0" | 29 |
| April 2026 | 89 | 68.9° / 51° | 8.7h | 2d | 1.7" | 23 |
| May 2026 | 94 | 72.3° / 53.5° | 11.5h | 1d | 0.25" | 31 |
| June 2026 | 96 | 77.6° / 56.7° | 12.1h | 0d | 0" | 30 |
| July 2026 | 95 | 77.9° / 58° | 11.6h | 0d | 0" | 31 |
| August 2026 | 93 | 79.3° / 59.1° | 10.7h | 3d | 0" | 31 |
| September 2026 | 93 | 79° / 57.2° | 9.8h | 1d | 0.01" | 28 |
| October 2026 | 92 | 76.9° / 54.6° | 8.3h | 1d | 0.08" | 29 |
Climate Trends
Average Temperature by Month
About the San Carlos climate charts
The temperature chart compares average monthly highs and lows at San Carlos, 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 San Carlos. 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 San Carlos, the warmest typical hour is 3 PM in August (79°F). The coldest is 6 AM in January (45°F).
- Fog: Fog or low cloud covers San Carlos in 19% of 7 AM hours in December, the foggiest month. It usually thins to a third of that by noon. May mornings are the least foggy (5%).
- Wind: From February through October, wind at San Carlos typically builds after 1 PM. In May it peaks around 5 PM, averaging 12 mph with 10% of those hours windy, while mornings average 4 mph.
- Cloud Cover: June middays are the clearest at San Carlos (19% average cloud cover), and December middays are the cloudiest (35%).
- Solar Radiation: The strongest typical sun at San Carlos comes at 1 PM in June, averaging 959 W/m².
How to read the hourly heatmaps for San Carlos
This heatmap shows how average temperature at San Carlos 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 San Carlos. 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 San Carlos 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 San Carlos 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 San Carlos 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 San Carlos
- October 2026 recap: October 2026 at San Carlos averaged a high of 77°F, 4°F warmer than the 1991-2020 normal of 73°F. It brought 0.08 in. of rain, compared with a normal of 0.89 in.
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 14.8 in. of rain to San Carlos, 75% of the 19.8 in. normal.
Location Details
San Carlos weather questions
Everything you need to know about weather and visiting San Carlos
What is the weather like at San Carlos today?
It's 52°F at San Carlos right now, with a comfort score of 76 (great). Monday's forecast high at San Carlos is 57°F, 7°F below the mid November normal of 64°F. The best window today is noon to 3 PM, at about 53°F with a 2 mph wind (comfort 59).
What is the best month to visit San Carlos?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at San Carlos are September, June, and July. The best hours are usually 10 AM to 1 PM in September, 11 AM to 2 PM in June, and 11 AM to 2 PM in July. The warm season lasts about 3 months, from Jul 1 to Sep 30, when the average high is 74°F or warmer. Highs peak around Sep 8 at about 76°F.
What are the warmest and coldest months at San Carlos?
September is the warmest month at San Carlos, with an average high of 76°F. December is the coldest, with an average low of 42°F.
When does the fog burn off at San Carlos?
Fog or low cloud covers San Carlos in 19% of 7 AM hours in December, the foggiest month. It usually thins to a third of that by noon. May mornings are the least foggy (5%).
When is it windiest at San Carlos?
From February through October, wind at San Carlos typically builds after 1 PM. In May it peaks around 5 PM, averaging 12 mph with 10% of those hours windy, while mornings average 4 mph.
How much rain does San Carlos get?
January is the wettest month (4.0 in.), out of about 19.8 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 14.8 in. of rain to San Carlos, 75% of the 19.8 in. normal.
How does San Carlos weather compare with Half Moon Bay?
Half Moon Bay, 9.7 miles away, runs about 13°F cooler than San Carlos on summer afternoons. It also has far more summer morning fog, 64% of morning hours compared with 7%.
Why is San Carlos called the City of Good Living?
The city calls Frederick Drake the "Father of San Carlos," and he coined the motto. The city's history page describes it as having a small-town feel and an ideal climate. San Carlos incorporated in June 1925.
What kind of place is San Carlos?
San Carlos, the self-styled City of Good Living, is a compact mid-Peninsula town between Belmont and Redwood City. It is built around a walkable Laurel Street downtown, one block west of El Camino Real and the Caltrain station. Behind it the hills rise toward Pulgas Ridge, where Big Canyon and Eaton parks hold more than 73 acres of natural open space with trails. On the bay side of Highway 101, San Carlos Airport sits at the end of the Steinberger Slough levee, beside the marshes.
What is San Carlos weather like in November?
November at San Carlos averages a high of 64°F and a low of 46°F, with 1.9 in. of rain over about 6 rainy days. About 10% of morning hours are foggy. Afternoon wind averages 5 mph.
More about San Carlos 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.
- City of San Carlos, About San Carlos (accessed 2026-10-27)
- City of San Carlos, Visit Trails (accessed 2026-10-27)
- Caltrain, San Carlos station (accessed 2026-10-27)
- MTC, San Francisco Bay Trail Map 5: Redwood Shores to Ravenswood Slough (accessed 2026-10-27)
Rendered 2026-11-15T12:16:27.800Z.