American Canyon Weather
Town • San Francisco Bay Area
American Canyon is the southern gateway to Napa County, a mostly residential city strung along Highway 29 between Vallejo and the Napa County Airport. Its western edge is the Napa River and a band of restored tidal marsh with about ten miles of wetland and Bay Trail paths. Its eastern edge climbs into grassy foothills, where the city's Newell Open Space Preserve runs as a working cattle ranch. Few places in the Bay Area put marsh and open ranchland this close together.
Plan your week
10-Day Forecast
Hour by hour
Hourly Forecast
Current Conditions
Comfort Breakdown
American Canyon weather today and through the year
It's 54°F at American Canyon right now (feels like 52°F), with 5 mph wind and a comfort score of 78. Today's forecast high at American Canyon is 60°F, 5°F below the mid November normal of 65°F. No fog in the forecast for today at American Canyon. In November, 17% of morning hours here are foggy on average. The best window today is 10 AM to 1 PM, at about 52°F with a 6 mph wind (comfort 60).
August is the warmest month at American Canyon, with an average high of 83°F. December is the coldest, with an average low of 39°F. January is the wettest month (4.6 in.), out of about 22.7 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at American Canyon are September, July, and August. The best hours are usually 11 AM to 2 PM in September, noon to 3 PM in July, and 11 AM to 2 PM in August.
American Canyon sits where the Napa Valley opens onto San Pablo Bay, so it gets bay air before any other Napa County town. On summer afternoons the sea breeze moves north off the bay and up the flat Napa River marshes, and the city feels it first and strongest. That is why it usually stays cooler and windier than the city of Napa, and far cooler than the upper valley around St. Helena and Calistoga.
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 American Canyon in the next few days
No active National Weather Service alerts for this location.
Fog
No fog in the forecast for today at American Canyon. In November, 17% of morning hours here are foggy on average.
Best time to go
The best window today is 10 AM to 1 PM, at about 52°F with a 6 mph wind (comfort 60).
Best day this week
Of the next 7 days, Friday looks best for American Canyon, with a 61°F high and midday comfort near 80. Today looks weakest (53).
Rain
Next good chance of rain: today (70%, about 0.45 in.).
Live weather map
Weather around American Canyon right now
Overcast and 54° at American Canyon right now.
About the live weather map for American Canyon
The map centers on American Canyon 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.
American Canyon vs nearby places
Typical summer conditions compared with American Canyon, 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 American Canyon |
|---|---|---|---|---|---|
| Vallejo | 4.9 mi | same | 18% | 9 mph | a very similar climate |
| Napa | 8.6 mi | +6°F | 25% | 9 mph | about 6°F warmer on summer afternoons |
| Benicia | 10.3 mi | +5°F | 11% | 12 mph | about 5°F warmer on summer afternoons |
| Claremont District | 22.2 mi | -8°F | 56% | 9 mph | more summer morning fog (56% vs 20% of morning hours) and about 8°F cooler on summer afternoons |
| Tiburon | 23.4 mi | -16°F | 27% | 15 mph | about 16°F cooler on summer afternoons and windier summer afternoons (15 vs 11 mph) |
| Angel Island State Park | 23.5 mi | -16°F | 27% | 15 mph | about 16°F cooler on summer afternoons and windier summer afternoons (15 vs 11 mph) |
Places with a climate like American Canyon's
- Sonoma (13 mi away): nearly the same temperatures every month
- Portola Valley (55 mi away): nearly the same temperatures every month
- Hayward (36 mi away): nearly the same temperatures every month
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the American Canyon climate comparisons mean
These cards compare recent conditions at American Canyon 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 American Canyon 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.
American Canyon weather by month
August is the warmest month at American Canyon, with an average high of 83°F. December is the coldest, with an average low of 39°F. January is the wettest month (4.6 in.), out of about 22.7 in. a year. Morning fog peaks in December, when fog or low cloud covers 27% of the hours from 6 to 10 AM. June has the clearest middays, with clouds covering about 12% of the sky from 11 AM to 3 PM.
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at American Canyon are September, July, and August. The best hours are usually 11 AM to 2 PM in September, noon to 3 PM in July, and 11 AM to 2 PM in August.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 57°F | 39°F | 4.6 in | 9 | 23% | 34% | 6 mph | 9.8 h | 58 |
| Feb | 62°F | 42°F | 4.3 in | 9 | 13% | 25% | 8 mph | 10.7 h | 62 |
| Mar | 65°F | 44°F | 3.2 in | 7 | 15% | 29% | 9 mph | 11.9 h | 65 |
| Apr | 69°F | 45°F | 1.5 in | 5 | 12% | 23% | 10 mph | 13.2 h | 75 |
| May | 74°F | 49°F | 0.8 in | 4 | 12% | 20% | 11 mph | 14.3 h | 78 |
| Jun | 80°F | 53°F | 0.2 in | 2 | 15% | 12% | 11 mph | 14.8 h | 83 |
| Jul | 82°F | 55°F | 0.0 in | 0 | 25% | 13% | 10 mph | 14.5 h | 86 |
| Aug | 83°F | 55°F | 0.1 in | 1 | 21% | 13% | 10 mph | 13.6 h | 86 |
| Sep | 82°F | 53°F | 0.1 in | 1 | 17% | 15% | 9 mph | 12.3 h | 89 |
| Oct | 76°F | 49°F | 1.1 in | 4 | 17% | 17% | 8 mph | 11.1 h | 82 |
| Nov | 65°F | 43°F | 2.3 in | 6 | 17% | 22% | 6 mph | 10.0 h | 69 |
| Dec | 57°F | 39°F | 4.5 in | 9 | 27% | 36% | 7 mph | 9.5 h | 55 |
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.
In summer, recent daily NOAA readings at American Canyon average about 6°F cooler than the 1991-2020 normals. The normals average over a wider area that also covers nearby terrain. Read the monthly highs as a rough range, and use the recent months below for what American Canyon has actually seen.
What makes American Canyon's weather different
When the fog burns off
1 PMwhen December fog usually thins (31% foggy at 6 AM)
Fog or low cloud covers American Canyon in 31% of 6 AM hours in December, the foggiest month. It usually thins to a third of that by 1 PM. April mornings are the least foggy (12%).
When the wind picks up
noonwhen afternoon wind builds, February–October
From February through October, wind at American Canyon typically builds after noon. In May it peaks around 4 PM, averaging 12 mph with 16% of those hours windy, while mornings average 6 mph.
Microclimate
+6°FNapa, 8.6 mi away, on summer afternoons
Napa, 8.6 miles away, runs about 6°F warmer than American Canyon on summer afternoons.
Daylight
9.5–14.8 hof daylight, Dec to Jun
Days at American Canyon range from about 9.5 hours in December to 14.8 hours in June. In mid-June the sun sets around 8:33 PM, and in mid-December around 4:54 PM.
Seasons at American Canyon
- Warm seasonJul 1 – Sep 25 · highs 81°F+
The warm season lasts about 2.9 months, from Jul 1 to Sep 25, when the average high is 81°F or warmer. Highs peak around Aug 8 at about 83°F.
- 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 12 – Apr 2 · 80% of the year's rain
The rainy season runs from Nov 12 to Apr 2, when a day has at least a 20% chance of measurable rain. That stretch brings 80% 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 Oct 29 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, American Canyon averaged 8 days a year at 90°F or hotter and 1 night a year at or below freezing. It averaged 14 days a year with at least half an inch of rain and 3 afternoons with wind of 20 mph or more at 2 PM. About 109 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 Feb 10, 2025 (32°F). The wettest day was Nov 23, 2024 (1.81 in.), and the strongest 2 PM gust was 43 mph on Feb 4, 2025.
- 8days at 90°F or hotter
- 1night at or below freezing
- 14days with ½ in. of rain or more
- 3afternoons with 20+ mph wind
- 109mornings with 3+ hours of fog or low cloud
- Hottest day99°FSep 9, 2026
- Coldest night32°FFeb 10, 2025
- Wettest day1.81 inNov 23, 2024
- Strongest 2 PM gust43 mphFeb 4, 2025
What shapes American Canyon's weather
American Canyon is a little farther from the Carquinez Strait than Vallejo, just to the south, and more tucked against the hills to the east. Even so, summer afternoons in the two cities usually run about the same. The foothills rise right behind town. On the Newell preserve, the open grassland heats up quickly in sun and catches the full force of the afternoon wind.
The flat marshland west of town is where cold air and fog collect. In winter, tule fog, a thick ground fog that forms on cold, calm nights, can sit over the river and wetlands into the morning. In heavy storms the low floodplains along the Napa River fill with water. In fall, the dry grass on the eastern hills makes offshore winds, dry winds blowing from inland toward the coast, a real fire concern.
Tips for visiting American Canyon
Walk the wetlands from Clarke Ranch
Clarke Ranch, at Eucalyptus Drive and Wetlands Edge Drive, is the gateway to the Wetland Edge trails. The trails and trailhead lot are open dawn to dusk.
Leash dogs on the river trails
Dogs must stay on leash on the Napa River and Bay Trail paths. They aren't allowed at Newell Open Space Preserve at all.
Expect Newell closures on Red Flag days
The city may close Newell during a Red Flag Warning, the Weather Service alert for hot, dry, windy weather that can spread fire fast. Its posted triggers are heat, strong wind and very low humidity, and extreme rain and lightning also close it.
Leave Newell's cattle gates as found
Newell is a working ranch with free-range cattle. Keep your distance from the herd and from wildlife, and watch for ticks and rattlesnakes.
Sign up for Alert Napa County
The city points residents and visitors to Alert Napa County for emergency notifications.
American Canyon through the seasons
- Spring (March–May)
- Spring brings green hills at Newell and mild days in the wetlands. Newell's loop trail access depends on the weather, so expect muddy or closed sections after storms.
- Summer (June–August)
- Summer is sunny and warm, with a strong afternoon breeze off San Pablo Bay. Hike Newell in the morning, before the grassland heats up.
- Fall (September–October)
- Early fall stays hot and dry, and Red Flag Warnings are most likely to close Newell before the first rains.
- Winter (November–February)
- Winter is the rainy season, with occasional morning fog over the Napa River marshes. It is also the best time to see water birds on the restored wetlands.
Activities and the weather that matters
- Wetland and Bay Trail walks: The paths are flat and shadeless, so go in the morning or on mild overcast days. Afternoon wind off the bay can be strong.
- Hiking at Newell Open Space Preserve: Hike Newell on cool, dry days. The city closes the preserve in Red Flag conditions and in extreme rain or lightning.
- Cycling: Calm mornings are easiest. Expect a headwind heading south toward Vallejo on summer afternoons.
Official sources and current conditions
- City of American Canyon: Wetlands and Napa River Bay Trail
- City of American Canyon: Newell Open Space Preserve
- City of American Canyon: Emergency preparedness
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 | 79 | 62.4° / 44.8° | 6.3h | 2d | 4.45" | 19 |
| December 2024 | 69 | 57.6° / 44.5° | 4.8h | 12d | 4.98" | 12 |
| January 2025 | 82 | 59° / 40.7° | 7.1h | 5d | 0.2" | 20 |
| February 2025 | 75 | 60.4° / 43.2° | 6.6h | 3d | 6.33" | 16 |
| March 2025 | 82 | 61.4° / 44.7° | 8h | 2d | 1.61" | 19 |
| April 2025 | 89 | 65.9° / 47.8° | 9.7h | 6d | 0.21" | 26 |
| May 2025 | 94 | 73.2° / 52° | 11.9h | 2d | 0.14" | 31 |
| June 2025 | 92 | 72.8° / 53.1° | 11.7h | 5d | 0" | 30 |
| July 2025 | 91 | 72.4° / 55.8° | 11.4h | 8d | 0" | 31 |
| August 2025 | 93 | 79.1° / 57.5° | 10.9h | 4d | 0" | 31 |
| September 2025 | 90 | 77° / 59.5° | 9.4h | 2d | 0.15" | 27 |
| October 2025 | 86 | 71.6° / 52.8° | 7.5h | 5d | 1.02" | 23 |
| November 2025 | 77 | 62.6° / 49.4° | 6.3h | 13d | 2.74" | 14 |
| December 2025 | 60 | 53.1° / 43.6° | 4.7h | 19d | 3.54" | 4 |
| January 2026 | 76 | 58.6° / 43.1° | 6.4h | 3d | 2.75" | 21 |
| February 2026 | 78 | 62.7° / 46° | 6.5h | 6d | 3.18" | 15 |
| March 2026 | 94 | 75.5° / 50.2° | 9.6h | 3d | 0.02" | 28 |
| April 2026 | 86 | 67.2° / 48.6° | 9.1h | 5d | 2.91" | 22 |
| May 2026 | 91 | 71.2° / 52.8° | 11.2h | 7d | 0.58" | 28 |
| June 2026 | 92 | 75.4° / 55.8° | 12.2h | 4d | 0" | 29 |
| July 2026 | 93 | 77° / 56.9° | 11.4h | 6d | 0" | 31 |
| August 2026 | 91 | 75.7° / 57.1° | 10.5h | 5d | 0" | 31 |
| September 2026 | 89 | 76.5° / 55.8° | 9.3h | 5d | 0.15" | 26 |
| October 2026 | 90 | 75.9° / 50.9° | 8.3h | 3d | 0.28" | 28 |
Climate Trends
Average Temperature by Month
About the American Canyon climate charts
The temperature chart compares average monthly highs and lows at American Canyon, 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 American Canyon. 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 American Canyon, the warmest typical hour is 4 PM in September (79°F). The coldest is 7 AM in February (44°F).
- Fog: Fog or low cloud covers American Canyon in 31% of 6 AM hours in December, the foggiest month. It usually thins to a third of that by 1 PM. April mornings are the least foggy (12%).
- Wind: From February through October, wind at American Canyon typically builds after noon. In May it peaks around 4 PM, averaging 12 mph with 16% of those hours windy, while mornings average 6 mph.
- Cloud Cover: June middays are the clearest at American Canyon (12% average cloud cover), and December middays are the cloudiest (36%).
- Solar Radiation: The strongest typical sun at American Canyon comes at 1 PM in June, averaging 985 W/m².
How to read the hourly heatmaps for American Canyon
This heatmap shows how average temperature at American Canyon 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 American Canyon. 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 American Canyon 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 American Canyon 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 American Canyon 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 American Canyon
- October 2026 recap: October 2026 at American Canyon averaged a high of 76°F, 4°F warmer than October 2025 (72°F).
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 16.9 in. of rain to American Canyon, 74% of the 22.7 in. normal.
Location Details
American Canyon weather questions
Everything you need to know about weather and visiting American Canyon
What is the weather like at American Canyon today?
It's 54°F at American Canyon right now, with a comfort score of 78 (great). Today's forecast high at American Canyon is 60°F, 5°F below the mid November normal of 65°F. The best window today is 10 AM to 1 PM, at about 52°F with a 6 mph wind (comfort 60).
What is the best month to visit American Canyon?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at American Canyon are September, July, and August. The best hours are usually 11 AM to 2 PM in September, noon to 3 PM in July, and 11 AM to 2 PM in August. The warm season lasts about 2.9 months, from Jul 1 to Sep 25, when the average high is 81°F or warmer. Highs peak around Aug 8 at about 83°F.
What are the warmest and coldest months at American Canyon?
August is the warmest month at American Canyon, with an average high of 83°F. December is the coldest, with an average low of 39°F.
When does the fog burn off at American Canyon?
Fog or low cloud covers American Canyon in 31% of 6 AM hours in December, the foggiest month. It usually thins to a third of that by 1 PM. April mornings are the least foggy (12%).
When is it windiest at American Canyon?
From February through October, wind at American Canyon typically builds after noon. In May it peaks around 4 PM, averaging 12 mph with 16% of those hours windy, while mornings average 6 mph.
How much rain does American Canyon get?
January is the wettest month (4.6 in.), out of about 22.7 in. a year. The rainy season runs from Nov 12 to Apr 2, when a day has at least a 20% chance of measurable rain. That stretch brings 80% of the year's rain. The 2025-26 rain year (Oct. 1 to Sep. 30) brought 16.9 in. of rain to American Canyon, 74% of the 22.7 in. normal.
How does American Canyon weather compare with Napa?
Napa, 8.6 miles away, runs about 6°F warmer than American Canyon on summer afternoons.
What kind of place is American Canyon?
American Canyon is the southern gateway to Napa County, a mostly residential city strung along Highway 29 between Vallejo and the Napa County Airport. Its western edge is the Napa River and a band of restored tidal marsh with about ten miles of wetland and Bay Trail paths. Its eastern edge climbs into grassy foothills, where the city's Newell Open Space Preserve runs as a working cattle ranch. Few places in the Bay Area put marsh and open ranchland this close together.
What is American Canyon weather like in November?
November at American Canyon averages a high of 65°F and a low of 43°F, with 2.3 in. of rain over about 6 rainy days. About 17% of morning hours are foggy. Afternoon wind averages 6 mph.
More about American Canyon weather
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 American Canyon, Wetlands & Napa River Bay Trail (accessed 2026-10-27)
- City of American Canyon, Newell Open Space Preserve (accessed 2026-10-27)
- City of American Canyon, home page (accessed 2026-10-27)
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