Suisun City Weather
Town • San Francisco Bay Area
Just south of downtown Fairfield, Suisun City grew up along Suisun Slough, the tidal channel that winds out into Suisun Marsh. The city describes the marsh as the largest remaining coastal wetland in California. Its historic Waterfront District, with restaurants a short walk from the city-run marina, faces open marsh instead of hills. Boats launched here can reach the sloughs of the marsh, and Grizzly Island Wildlife Area lies farther out in the marsh, about 11 miles from Fairfield.
Plan your week
10-Day Forecast
Hour by hour
Hourly Forecast
Current Conditions
Comfort Breakdown
Suisun City weather today and through the year
It's 52°F at Suisun City right now (feels like 51°F), with 1 mph wind and a comfort score of 76. Monday's forecast high at Suisun City is 57°F, 9°F below the mid November normal of 66°F. The best window today is 9 AM to noon, at about 53°F with a 7 mph wind (comfort 59).
July is the warmest month at Suisun City, with an average high of 89°F. December is the coldest, with an average low of 39°F. December is the wettest month (4.4 in.), out of about 21.1 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Suisun City are June, September, and August. The best hours are usually 9 AM to noon in June, 9 AM to noon in September, and 9 AM to noon in August.
Suisun City shares Fairfield's basic setup, downwind of the Carquinez Strait, where cool ocean air pours inland on summer afternoons. The difference is exposure. Fairfield backs up against hills on its west and north sides, while Suisun City sits barely above the tide on the edge of open marsh. The west wind crosses miles of flat water and tule, a tall marsh reed, with almost nothing to slow it.
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 Suisun City in the next few days
No active National Weather Service alerts for this location.
Best time to go
The best window today is 9 AM to noon, at about 53°F with a 7 mph wind (comfort 59).
Best day this week
Of the next 7 days, Friday looks best for Suisun City, with a 61°F high and midday comfort near 77. Wednesday looks weakest (41).
Rain
Next good chance of rain: today (75%, about 0.21 in.).
Live weather map
Weather around Suisun City right now
Overcast and 52° at Suisun City right now.
About the live weather map for Suisun City
The map centers on Suisun City 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.
Suisun City vs nearby places
Typical summer conditions compared with Suisun City, 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 Suisun City |
|---|---|---|---|---|---|
| Fairfield | 0.8 mi | same | 5% | 11 mph | same 3 km weather-model cell, so our hourly data cannot tell them apart |
| Vacaville | 8.7 mi | +5°F | 1% | 9 mph | about 5°F warmer on summer afternoons |
| Wooden Valley | 10.4 mi | -1°F | 3% | 10 mph | about 34% more rain a year |
| Yountville | 20.7 mi | +2°F | 29% | 8 mph | more summer morning fog (29% vs 5% of morning hours) and about 30% more rain a year |
| Briones Regional Park | 21.9 mi | -8°F | 23% | 11 mph | about 8°F cooler on summer afternoons and more summer morning fog (23% vs 5% of morning hours) |
| Wildcat Canyon Regional Park | 24.8 mi | -17°F | 42% | 11 mph | about 17°F cooler on summer afternoons and more summer morning fog (42% vs 5% of morning hours) |
Places with a climate like Suisun City's
- Pittsburg (17 mi away): nearly the same temperatures every month
- Antioch (21 mi away): nearly the same temperatures every month
- Black Diamond Mines Regional Preserve (22 mi away): nearly the same temperatures every month
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the Suisun City climate comparisons mean
These cards compare recent conditions at Suisun City 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 Suisun City 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.
Suisun City weather by month
July is the warmest month at Suisun City, with an average high of 89°F. December is the coldest, with an average low of 39°F. December is the wettest month (4.4 in.), out of about 21.1 in. a year. Morning fog peaks in December, when fog or low cloud covers 30% of the hours from 6 to 10 AM. July has the clearest middays, with clouds covering about 4% of the sky from 11 AM to 3 PM.
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Suisun City are June, September, and August. The best hours are usually 9 AM to noon in June, 9 AM to noon in September, and 9 AM to noon in August.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 57°F | 40°F | 4.3 in | 9 | 28% | 34% | 6 mph | 9.8 h | 58 |
| Feb | 62°F | 42°F | 4.1 in | 8 | 12% | 22% | 7 mph | 10.7 h | 63 |
| Mar | 67°F | 45°F | 2.9 in | 7 | 7% | 26% | 8 mph | 11.9 h | 68 |
| Apr | 72°F | 47°F | 1.3 in | 5 | 5% | 19% | 9 mph | 13.2 h | 79 |
| May | 78°F | 52°F | 0.7 in | 3 | 6% | 13% | 11 mph | 14.3 h | 79 |
| Jun | 86°F | 56°F | 0.1 in | 2 | 4% | 5% | 11 mph | 14.8 h | 83 |
| Jul | 89°F | 58°F | 0.0 in | 0 | 7% | 4% | 11 mph | 14.6 h | 80 |
| Aug | 89°F | 57°F | 0.0 in | 1 | 4% | 4% | 10 mph | 13.6 h | 81 |
| Sep | 86°F | 56°F | 0.1 in | 1 | 2% | 7% | 9 mph | 12.3 h | 83 |
| Oct | 78°F | 51°F | 0.9 in | 4 | 4% | 11% | 7 mph | 11.1 h | 81 |
| Nov | 66°F | 44°F | 2.2 in | 6 | 11% | 22% | 6 mph | 10.0 h | 76 |
| Dec | 57°F | 39°F | 4.4 in | 9 | 30% | 37% | 6 mph | 9.5 h | 54 |
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 Suisun City's weather different
When the fog burns off
34%of 7 AM hours foggy in December
Fog or low cloud covers Suisun City in 34% of 7 AM hours in December, the foggiest month. It thins slowly and often lasts into the early afternoon. September mornings are the least foggy (2%).
When the wind picks up
2 PMwhen afternoon wind builds, March–September
From March through September, wind at Suisun City typically builds after 2 PM. In June it peaks around 5 PM, averaging 13 mph with 20% of those hours windy, while mornings average 9 mph.
Hot hours
4 habove 85°F on a typical July afternoon
In July, the average temperature stays at or above 85°F for 4 hours a day.
Microclimate
+5°FVacaville, 8.7 mi away, on summer afternoons
Vacaville, 8.7 miles away, runs about 5°F warmer than Suisun City on summer afternoons.
Model resolution
2 placesshare one 3 km NOAA HRRR grid cell
Suisun City shares one 3 km grid cell in NOAA's HRRR model with Fairfield. The hourly fog, wind, cloud, and temperature patterns on this site are the same for both. Real differences between them come from hills, elevation, and wind exposure that the model cannot resolve.
Daylight
9.5–14.8 hof daylight, Dec to Jun
Days at Suisun City 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 Suisun City
- Warm seasonJun 25 – Sep 23 · highs 86°F+
The warm season lasts about 3 months, from Jun 25 to Sep 23, when the average high is 86°F or warmer. Highs peak around Jul 8 at about 89°F.
- Hot afternoonsJun 7 – Sep 25 · highs 85°F+
Average highs reach 85°F or more from Jun 7 to Sep 25.
- Cool seasonNov 26 – Feb 27 · highs 64°F or lower
The cool season runs from Nov 26 to Feb 27, when the average high is 64°F or lower. The coldest nights come around Dec 8, with an average low near 39°F.
- Rainy seasonNov 16 – Mar 29 · 79% of the year's rain
The rainy season runs from Nov 16 to Mar 29, when a day has at least a 20% chance of measurable rain. That stretch brings 79% 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 1 and half of its annual total by Jan 23.
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, Suisun City averaged 31 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 1 afternoon with wind of 20 mph or more at 2 PM. About 56 mornings a year had 3 or more hours of fog or low cloud.
In the same record, the hottest day was Jun 11, 2026 (103°F) and the coldest night was Feb 10, 2025 (31°F). The wettest day was Nov 23, 2024 (2.03 in.), and the strongest 2 PM gust was 42 mph on Feb 13, 2025.
- 31days at 90°F or hotter
- 1night at or below freezing
- 14days with ½ in. of rain or more
- 1afternoon with 20+ mph wind
- 56mornings with 3+ hours of fog or low cloud
- Hottest day103°FJun 11, 2026
- Coldest night31°FFeb 10, 2025
- Wettest day2.03 inNov 23, 2024
- Strongest 2 PM gust42 mphFeb 13, 2025
What shapes Suisun City's weather
With open marsh to the west, Suisun City's waterfront is one of the breeziest spots in the Fairfield area on a summer afternoon. The San Francisco Bay Area Water Trail warns that frequent afternoon winds at the marina can make paddling back to the launch hard. Mornings are usually the calm part of the day on the slough.
The marsh also takes a little off the extremes. Water and wet ground warm and cool more slowly than the dry farmland toward Vacaville, so hot afternoons here tend to be a bit less harsh. On calm, damp winter nights, low fog can form over the sloughs and linger into the morning.
Tides shape a visit here as much as weather does. Suisun Slough rises and falls with the tide, and low water exposes mudflats that can leave small boats stranded well short of the docks.
Tips for visiting Suisun City
Paddle the slough in the morning
Afternoon winds are frequent at the Suisun City Marina and can make the return trip difficult.
Check the tide before launching
Mudflats appear at low tide and can strand boaters, and the boarding piers shift with the water level.
Give rail habitat a wide berth
Stay at least 50 feet from habitat of the Ridgway's rail, an endangered marsh bird, and avoid channels narrower than 100 feet, especially at high tide.
Eat on the waterfront after the wind
Restaurants sit within walking distance of the marina in the Waterfront District, and evenings are often calmer than mid-afternoon.
Check Grizzly Island dates before driving out
The wildlife area closes to all non-hunting uses from late July to early February and sometimes closes for winter flooding. Call (707) 425-3828 for exact dates.
Suisun City through the seasons
- Spring (March–May)
- Spring is mild and grows breezier each month. It is a good season to bird the marsh, since Grizzly Island is open to non-hunters until its late-July closure.
- Summer (June–August)
- A steady west wind blows off the marsh on most summer afternoons. Plan paddling for early in the day.
- Fall (September–November)
- The wind eases and waterfowl start arriving. Hunting season is underway in the marsh, so check with the California Department of Fish and Wildlife before heading out.
- Winter (December–February)
- Winter brings rain, still gray mornings, and the year's biggest flocks. More than 100,000 waterfowl spend the winter at Grizzly Island. Flooding occasionally closes the wildlife area.
Activities and the weather that matters
- Kayaking and small-boat trips on Suisun Slough: Calm mornings and a mid-level tide are ideal. Afternoon wind and low-tide mudflats are the main hazards.
- Birding at Grizzly Island and Peytonia Slough: Winter brings the most waterfowl, but Grizzly Island stays closed to non-hunters from late July to early February. February, after it reopens, is the best time to see the big flocks there.
- Fishing the marsh: Calm mornings are easiest. The state wildlife department lists striped bass, catfish, crappie, and white sturgeon among the catch.
- Strolling the Waterfront District: The waterfront is best in the evening, once the afternoon wind off the marsh dies down.
Official sources and current conditions
- City of Suisun City: Suisun City Marina
- San Francisco Bay Area Water Trail: Suisun City Marina
- CDFW: Grizzly Island Wildlife Area
- National Weather Service Sacramento
- Alert Solano emergency notifications
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 | 80 | 63° / 44.7° | 6.3h | 3d | 4.77" | 18 |
| December 2024 | 69 | 58.1° / 43.4° | 4.6h | 14d | 4.54" | 11 |
| January 2025 | 83 | 60.1° / 39.6° | 7.3h | 4d | 0.16" | 25 |
| February 2025 | 79 | 61.8° / 43.8° | 6.8h | 4d | 6.3" | 18 |
| March 2025 | 86 | 63.5° / 45.3° | 8.3h | 1d | 1.28" | 22 |
| April 2025 | 94 | 70.3° / 49.1° | 10.2h | 0d | 0.17" | 28 |
| May 2025 | 94 | 78.5° / 54.3° | 12.4h | 1d | 0.19" | 31 |
| June 2025 | 94 | 80.5° / 54.8° | 12.7h | 0d | 0" | 30 |
| July 2025 | 93 | 81.2° / 56.7° | 12.4h | 1d | 0" | 31 |
| August 2025 | 90 | 87.8° / 59.6° | 11.6h | 0d | 0" | 28 |
| September 2025 | 90 | 83.2° / 61.4° | 9.8h | 0d | 0.3" | 26 |
| October 2025 | 89 | 74.2° / 53.8° | 7.8h | 1d | 1.58" | 26 |
| November 2025 | 78 | 63.5° / 49.5° | 6.2h | 10d | 2.59" | 16 |
| December 2025 | 57 | 52.5° / 44.1° | 3.2h | 23d | 3.45" | 2 |
| January 2026 | 72 | 58.2° / 41.9° | 6.1h | 13d | 3.19" | 13 |
| February 2026 | 80 | 64.1° / 45.4° | 6.7h | 5d | 2.97" | 19 |
| March 2026 | 94 | 78.3° / 52.4° | 9.7h | 0d | 0" | 31 |
| April 2026 | 89 | 70° / 50.6° | 9.4h | 2d | 2.74" | 24 |
| May 2026 | 92 | 76.2° / 54.7° | 11.6h | 0d | 0.94" | 30 |
| June 2026 | 94 | 82.6° / 57.7° | 12.9h | 0d | 0" | 29 |
| July 2026 | 92 | 85.7° / 59.2° | 11.9h | 0d | 0" | 29 |
| August 2026 | 92 | 85.7° / 58.9° | 11.1h | 0d | 0" | 30 |
| September 2026 | 92 | 82.2° / 57.9° | 10h | 0d | 0.06" | 27 |
| October 2026 | 88 | 79.9° / 54.5° | 8.3h | 1d | 0.35" | 26 |
Climate Trends
Average Temperature by Month
About the Suisun City climate charts
The temperature chart compares average monthly highs and lows at Suisun City, 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 Suisun City. 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 Suisun City, the warmest typical hour is 4 PM in August (88°F). The coldest is 7 AM in December (42°F).
- Fog: Fog or low cloud covers Suisun City in 34% of 7 AM hours in December, the foggiest month. It thins slowly and often lasts into the early afternoon. September mornings are the least foggy (2%).
- Wind: From March through September, wind at Suisun City typically builds after 2 PM. In June it peaks around 5 PM, averaging 13 mph with 20% of those hours windy, while mornings average 9 mph.
- Cloud Cover: July middays are the clearest at Suisun City (4% average cloud cover), and December middays are the cloudiest (37%).
- Solar Radiation: The strongest typical sun at Suisun City comes at 1 PM in June, averaging 999 W/m².
How to read the hourly heatmaps for Suisun City
This heatmap shows how average temperature at Suisun City 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 Suisun City. 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 Suisun City 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 Suisun City 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 Suisun City 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 Suisun City
- October 2026 recap: October 2026 at Suisun City averaged a high of 80°F, 6°F warmer than October 2025 (74°F).
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 17.5 in. of rain to Suisun City, 83% of the 21.1 in. normal.
Location Details
Suisun City weather questions
Everything you need to know about weather and visiting Suisun City
What is the weather like at Suisun City today?
It's 52°F at Suisun City right now, with a comfort score of 76 (great). Monday's forecast high at Suisun City is 57°F, 9°F below the mid November normal of 66°F. The best window today is 9 AM to noon, at about 53°F with a 7 mph wind (comfort 59).
What is the best month to visit Suisun City?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Suisun City are June, September, and August. The best hours are usually 9 AM to noon in June, 9 AM to noon in September, and 9 AM to noon in August. The warm season lasts about 3 months, from Jun 25 to Sep 23, when the average high is 86°F or warmer. Highs peak around Jul 8 at about 89°F.
What are the warmest and coldest months at Suisun City?
July is the warmest month at Suisun City, with an average high of 89°F. December is the coldest, with an average low of 39°F.
When does the fog burn off at Suisun City?
Fog or low cloud covers Suisun City in 34% of 7 AM hours in December, the foggiest month. It thins slowly and often lasts into the early afternoon. September mornings are the least foggy (2%).
When is it windiest at Suisun City?
From March through September, wind at Suisun City typically builds after 2 PM. In June it peaks around 5 PM, averaging 13 mph with 20% of those hours windy, while mornings average 9 mph.
How much rain does Suisun City get?
December is the wettest month (4.4 in.), out of about 21.1 in. a year. The rainy season runs from Nov 16 to Mar 29, when a day has at least a 20% chance of measurable rain. That stretch brings 79% of the year's rain. The 2025-26 rain year (Oct. 1 to Sep. 30) brought 17.5 in. of rain to Suisun City, 83% of the 21.1 in. normal.
How does Suisun City weather compare with Vacaville?
Vacaville, 8.7 miles away, runs about 5°F warmer than Suisun City on summer afternoons.
What kind of place is Suisun City?
Just south of downtown Fairfield, Suisun City grew up along Suisun Slough, the tidal channel that winds out into Suisun Marsh. The city describes the marsh as the largest remaining coastal wetland in California. Its historic Waterfront District, with restaurants a short walk from the city-run marina, faces open marsh instead of hills. Boats launched here can reach the sloughs of the marsh, and Grizzly Island Wildlife Area lies farther out in the marsh, about 11 miles from Fairfield.
What is Suisun City weather like in November?
November at Suisun City averages a high of 66°F and a low of 44°F, with 2.2 in. of rain over about 6 rainy days. About 11% of morning hours are foggy. Afternoon wind averages 6 mph.
More about Suisun City 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 Suisun City, Suisun City Marina (accessed 2026-10-27)
- San Francisco Bay Area Water Trail, Suisun City Marina trailhead (accessed 2026-10-27)
- California Department of Fish and Wildlife, Grizzly Island Wildlife Area (accessed 2026-10-27)
Rendered 2026-11-15T12:26:26.421Z.