Cobb Mountain Area Weather
Viewpoint • San Francisco Bay Area
Cobb Mountain, a volcanic peak in southern Lake County, is the highest summit in the Mayacamas Mountains. It looks down on The Geysers steam field to the west. The name also covers the small forested communities along Highway 175 on its flanks, including Cobb, Loch Lomond, Whispering Pines, and the old Hobergs resort area. Pine and mixed forest replace the oaks and chaparral of the valleys below. Much of the mountain burned in the 2015 Valley Fire.
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10-Day Forecast
Hour by hour
Hourly Forecast
Current Conditions
Comfort Breakdown
Cobb Mountain Area weather today and through the year
It's 48°F at Cobb Mountain Area right now (feels like 40°F), with 15 mph wind and a comfort score of 53. Today's forecast high at Cobb Mountain Area is 50°F, 6°F below the mid November normal of 56°F. Fog is forecast today until about noon at Cobb Mountain Area. In November, fog here usually thins by 1 PM. The best window today is 2 PM to 5 PM, at about 40°F with a 9 mph wind (comfort 36).
July is the warmest month at Cobb Mountain Area, with an average high of 83°F. February is the coldest, with an average low of 37°F. December is the wettest month (12.5 in.), out of about 55.1 in. a year. By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Cobb Mountain Area are June, September, and August. The best hours are usually 10 AM to 1 PM in June, 10 AM to 1 PM in September, and 8 AM to 11 AM in August.
Cobb's climate is set by height. The communities sit well up the mountain's flanks, far from the coastal fog. They are high enough to stay out of the hot air that settles over Middletown and the Clear Lake basin on summer afternoons. Days under the pines are warm rather than baking, and nights cool off fast.
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 Cobb Mountain Area in the next few days
No active National Weather Service alerts for this location.
Fog
Fog is forecast today until about noon at Cobb Mountain Area. In November, fog here usually thins by 1 PM.
Best time to go
The best window today is 2 PM to 5 PM, at about 40°F with a 9 mph wind (comfort 36).
Hiking conditions
Best hiking day this week: Friday, with 2 daylight hours that are dry, 45 to 80°F, and under 18 mph wind. 0 of the next 7 days have at least 4 such hours.
Best day this week
Of the next 7 days, Friday looks best for Cobb Mountain Area, with a 49°F high and midday comfort near 58. Today looks weakest (32).
Rain
Next good chance of rain: today (90%, about 0.69 in.).
Live weather map
Weather around Cobb Mountain Area right now
Overcast and 48° at Cobb Mountain Area right now.
About the live weather map for Cobb Mountain Area
The map centers on Cobb Mountain Area 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.
Cobb Mountain Area vs nearby places
Typical summer conditions compared with Cobb Mountain Area, 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 Cobb Mountain Area |
|---|---|---|---|---|---|
| Boggs Mountain Demonstration State Forest | 2.2 mi | same | 5% | 6 mph | a very similar climate |
| Middletown | 8 mi | +6°F | 17% | 10 mph | about 6°F warmer on summer afternoons and 1,690 ft lower |
| Geyserville | 13.3 mi | +7°F | 22% | 9 mph | 2,478 ft lower and about 7°F warmer on summer afternoons |
| Cloverdale | 16 mi | +8°F | 18% | 9 mph | 2,412 ft lower and about 8°F warmer on summer afternoons |
| Calistoga | 19.2 mi | +4°F | 29% | 9 mph | more summer morning fog (29% vs 6% of morning hours) and 2,378 ft lower |
| Windsor | 20.4 mi | +3°F | 30% | 9 mph | more summer morning fog (30% vs 6% of morning hours) and 2,642 ft lower |
Places with a climate like Cobb Mountain Area's
- Lick Observatory (Mt. Hamilton) (119 mi away): similar temperatures through the year
- Henry W. Coe State Park (131 mi away): similar temperatures through the year
- Robert Louis Stevenson State Park (14 mi away): similar temperatures through the year
Climate Dashboard
Current conditions vs. NOAA normals and recent destination baseline
What the Cobb Mountain Area climate comparisons mean
These cards compare recent conditions at Cobb Mountain Area 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 Cobb Mountain Area 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.
Cobb Mountain Area weather by month
July is the warmest month at Cobb Mountain Area, with an average high of 83°F. February is the coldest, with an average low of 37°F. December is the wettest month (12.5 in.), out of about 55.1 in. a year. Morning fog peaks in December, when fog or low cloud covers 40% of the hours from 6 to 10 AM. July has the clearest middays, with clouds covering about 2% of the sky from 11 AM to 3 PM.
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Cobb Mountain Area are June, September, and August. The best hours are usually 10 AM to 1 PM in June, 10 AM to 1 PM in September, and 8 AM to 11 AM in August.
| Month | Avg high | Avg low | Rain | Rainy days | Morning fog | Midday cloud | Afternoon wind | Daylight | Comfort |
|---|---|---|---|---|---|---|---|---|---|
| Jan | 51°F | 38°F | 11.6 in | 14 | 36% | 34% | 8 mph | 9.7 h | 18 |
| Feb | 51°F | 37°F | 8.7 in | 12 | 25% | 31% | 9 mph | 10.7 h | 15 |
| Mar | 54°F | 38°F | 7.5 in | 12 | 25% | 33% | 8 mph | 11.9 h | 26 |
| Apr | 59°F | 39°F | 3.5 in | 8 | 20% | 23% | 8 mph | 13.2 h | 61 |
| May | 67°F | 45°F | 2.6 in | 7 | 11% | 15% | 8 mph | 14.3 h | 74 |
| Jun | 75°F | 52°F | 0.4 in | 3 | 3% | 5% | 8 mph | 14.9 h | 89 |
| Jul | 83°F | 58°F | 0.0 in | 0 | 6% | 2% | 7 mph | 14.6 h | 85 |
| Aug | 83°F | 57°F | 0.1 in | 1 | 8% | 3% | 7 mph | 13.6 h | 86 |
| Sep | 79°F | 54°F | 0.2 in | 2 | 14% | 8% | 7 mph | 12.3 h | 89 |
| Oct | 69°F | 49°F | 2.4 in | 7 | 21% | 14% | 7 mph | 11.1 h | 75 |
| Nov | 56°F | 41°F | 5.6 in | 10 | 27% | 22% | 7 mph | 10.0 h | 38 |
| Dec | 50°F | 37°F | 12.5 in | 15 | 40% | 35% | 8 mph | 9.5 h | 18 |
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 Cobb Mountain Area's weather different
Among the 10 San Francisco Bay Area viewpoints we track, Cobb Mountain Area has the warmest summer afternoons and the 3rd-least foggy summer mornings. It also has the 3rd-sunniest summer middays and the 2nd-calmest summer afternoons.
- #1of 10
warmest summer afternoonsamong San Francisco Bay Area viewpoints
- #3of 10
least foggy summer morningsamong San Francisco Bay Area viewpoints
- #3of 10
sunniest summer middaysamong San Francisco Bay Area viewpoints
- #2of 10
calmest summer afternoonsamong San Francisco Bay Area viewpoints
When the fog burns off
46%of 5 AM hours foggy in December
Fog or low cloud covers Cobb Mountain Area in 46% of 5 AM hours in December, the foggiest month. It often lingers, and 24% of mid-afternoon hours are still foggy. June mornings are the least foggy (3%).
Wind
8 mphtypical afternoon wind, with no strong daily build-up
Cobb Mountain Area has no strong afternoon wind build-up. Afternoons average about 8 mph year-round, and June is the windiest month, with hourly averages near 9 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.
Elevation
+6°Fsummer afternoons at Middletown, 1,690 ft down
Middletown sits 1,690 ft lower, 8 miles away. Its summer highs average 6°F warmer and its winter lows 1°F colder than Cobb Mountain Area.
Daylight
9.5–14.9 hof daylight, Dec to Jun
Days at Cobb Mountain Area range from about 9.5 hours in December to 14.9 hours in June. In mid-June the sun sets around 8:38 PM, and in mid-December around 4:56 PM.
Seasons at Cobb Mountain Area
- Warm seasonJun 27 – Sep 26 · highs 77°F+
The warm season lasts about 3 months, from Jun 27 to Sep 26, when the average high is 77°F or warmer. Highs peak around Jul 8 at about 83°F.
- Cool seasonDec 2 – Mar 1 · highs 53°F or lower
The cool season runs from Dec 2 to Mar 1, when the average high is 53°F or lower. The coldest nights come around Feb 8, with an average low near 37°F.
- Rainy seasonOct 27 – Apr 22 · 89% of the year's rain
The rainy season runs from Oct 27 to Apr 22, when a day has at least a 25% chance of measurable rain. That stretch brings 89% 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 13 and half of its annual total by Jan 19.
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, Cobb Mountain Area averaged 16 days a year at 90°F or hotter and 13 nights a year at or below freezing. It averaged 32 days a year with at least half an inch of rain and 6 afternoons with wind of 20 mph or more at 2 PM. About 93 mornings a year had 3 or more hours of fog or low cloud.
In the same record, the hottest day was Aug 8, 2026 (99°F) and the coldest night was Feb 18, 2026 (26°F). The wettest day was Nov 21, 2024 (7.08 in.), and the strongest 2 PM gust was 60 mph on Feb 4, 2025.
- 16days at 90°F or hotter
- 13nights at or below freezing
- 32days with ½ in. of rain or more
- 6afternoons with 20+ mph wind
- 93mornings with 3+ hours of fog or low cloud
- Hottest day99°FAug 8, 2026
- Coldest night26°FFeb 18, 2026
- Wettest day7.08 inNov 21, 2024
- Strongest 2 PM gust60 mphFeb 4, 2025
What shapes Cobb Mountain Area's weather
Cobb's height helps on winter nights too. Cold air drains downhill into the valleys after dark. On clear, calm nights, mid-slope spots around Cobb can stay milder than Middletown's valley floor, even though Cobb's afternoons are cooler.
Cobb Mountain is the first tall barrier that Pacific storms reach after crossing the Sonoma County hills. Air forced up its western slopes drops heavy rain, so Cobb is far wetter than the Clear Lake basin east of it. In the coldest storms that rain turns to snow, and the mountain is dusted a few times a year, as Mount St. Helena is.
Dry summers and steep, forested slopes make fire the main hazard. The 2015 Valley Fire ran from Cobb down through Middletown in a single day. In October 2019 the Lake County Sheriff put Cobb Mountain under an evacuation warning while the Kincade Fire burned in The Geysers to the west.
Tips for visiting Cobb Mountain Area
Carry chains in winter storms
In snow, chains have been required on Cobb-area county roads and on Highway 175 through Cobb unless you have four-wheel drive with snow tires.
Check Highway 175 before you go
In cold storms Caltrans can impose chain controls, rules that require tire chains, on Highway 175. Its QuickMap site and its highway information line at (800) 427-7623 list chain controls and closures.
Register for LakeCoAlerts
LakeCoAlerts is the county's emergency messaging system for fires and storms. Genasys Protect shows your evacuation zone on a map, and you can use it without signing up.
Use the public trails at Boggs
Boggs Mountain Demonstration State Forest is the nearby public trail network, and Friends of Boggs Mountain posts its current trail map.
Cobb Mountain Area through the seasons
- Spring (March–May)
- Seasonal pools on the mountain, which fill in winter and dry by summer, support rare plants such as Boggs Lake hedge-hyssop. The slopes are at their greenest.
- Summer (June–August)
- Summer brings warm, dry days and cool nights, usually more comfortable than the valleys below. Fire danger builds as the forest dries.
- Fall (September–November)
- Peak fire weather until the rains start. In October 2019 the Kincade Fire put Cobb Mountain under an evacuation warning.
- Winter (December–February)
- Winter is wet and cold, with snow a few times a year. In a January 2008 storm residents reported up to 10 inches above 3,000 feet, and chains were required on Highway 175.
Activities and the weather that matters
- Scenic drives on Highway 175: Best on clear days just after a winter storm, when snow may dust the summit. Check chain controls first.
- Mountain biking and hiking at Boggs Mountain: Boggs Mountain is cooler than the valley floor in summer, and its trails are best on dry spring and fall days.
- Escaping valley heat: On hot summer days the forest at Cobb's elevation is noticeably cooler than Middletown or Clear Lake.
Official sources and current conditions
- Lake County: Lake Co Ready (alerts and evacuation zones)
- Caltrans winter driving and road conditions
- Friends of Boggs Mountain
- National Weather Service forecast: Cobb area
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 | 63 | 51.2° / 39.8° | 5.9h | 9d | 21.76" | 12 |
| December 2024 | 61 | 53.3° / 43.7° | 5h | 12d | 14.34" | 10 |
| January 2025 | 77 | 54.1° / 41.8° | 7.4h | 5d | 0.8" | 19 |
| February 2025 | 62 | 50.9° / 39° | 6.1h | 11d | 20.42" | 10 |
| March 2025 | 62 | 50.4° / 37.8° | 7.3h | 9d | 9.93" | 9 |
| April 2025 | 85 | 61.9° / 45.6° | 9.5h | 7d | 1.76" | 23 |
| May 2025 | 96 | 70.4° / 50.6° | 12.7h | 1d | 0.24" | 30 |
| June 2025 | 96 | 79.7° / 60.4° | 13h | 0d | 0" | 30 |
| July 2025 | 95 | 82.2° / 64.1° | 12.6h | 0d | 0" | 31 |
| August 2025 | 91 | 85.6° / 66.5° | 11.6h | 2d | 0" | 31 |
| September 2025 | 90 | 76.9° / 61.1° | 9.7h | 3d | 0.72" | 26 |
| October 2025 | 82 | 64.2° / 50.6° | 7.5h | 13d | 2.92" | 22 |
| November 2025 | 74 | 59.2° / 47.9° | 6.4h | 13d | 8.02" | 14 |
| December 2025 | 64 | 56.1° / 47.5° | 5h | 20d | 16.39" | 10 |
| January 2026 | 72 | 54.9° / 45.9° | 6.3h | 9d | 10.67" | 17 |
| February 2026 | 63 | 53° / 42.7° | 6.1h | 11d | 8.93" | 12 |
| March 2026 | 93 | 68.7° / 52.1° | 9.7h | 1d | 0" | 29 |
| April 2026 | 78 | 58° / 44° | 9h | 8d | 8.71" | 19 |
| May 2026 | 92 | 69.5° / 51.9° | 11.8h | 4d | 0.84" | 28 |
| June 2026 | 96 | 79.6° / 59.8° | 12.8h | 0d | 0" | 30 |
| July 2026 | 91 | 84.4° / 64.9° | 12.3h | 0d | 0.04" | 31 |
| August 2026 | 89 | 85.5° / 67.1° | 11.4h | 3d | 0" | 29 |
| September 2026 | 92 | 75.7° / 56.8° | 10.3h | 6d | 0.37" | 29 |
| October 2026 | 88 | 71.8° / 55.9° | 8.5h | 2d | 0.04" | 29 |
Climate Trends
Average Temperature by Month
About the Cobb Mountain Area climate charts
The temperature chart compares average monthly highs and lows at Cobb Mountain Area, 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 Cobb Mountain Area. 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 Cobb Mountain Area, the warmest typical hour is 4 PM in July (86°F). The coldest is 7 AM in February (39°F).
- Fog: Fog or low cloud covers Cobb Mountain Area in 46% of 5 AM hours in December, the foggiest month. It often lingers, and 24% of mid-afternoon hours are still foggy. June mornings are the least foggy (3%).
- Wind: Cobb Mountain Area has no strong afternoon wind build-up. Afternoons average about 8 mph year-round, and June is the windiest month, with hourly averages near 9 mph.
- Cloud Cover: July middays are the clearest at Cobb Mountain Area (2% average cloud cover), and December middays are the cloudiest (35%).
- Solar Radiation: The strongest typical sun at Cobb Mountain Area comes at 1 PM in July, averaging 1005 W/m².
How to read the hourly heatmaps for Cobb Mountain Area
This heatmap shows how average temperature at Cobb Mountain Area 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 Cobb Mountain Area. 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 Cobb Mountain Area 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 Cobb Mountain Area 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 Cobb Mountain Area 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 Cobb Mountain Area
- October 2026 recap: October 2026 at Cobb Mountain Area averaged a high of 72°F, 8°F warmer than October 2025 (64°F).
- Rain year: The 2025-26 rain year (Oct. 1 to Sep. 30) brought 56.9 in. of rain to Cobb Mountain Area, 103% of the 55.1 in. normal.
Location Details
Cobb Mountain Area weather questions
Everything you need to know about weather and visiting Cobb Mountain Area
What is the weather like at Cobb Mountain Area today?
It's 48°F at Cobb Mountain Area right now, with a comfort score of 53 (fair). Today's forecast high at Cobb Mountain Area is 50°F, 6°F below the mid November normal of 56°F. The best window today is 2 PM to 5 PM, at about 40°F with a 9 mph wind (comfort 36).
What is the best month to visit Cobb Mountain Area?
By typical temperature, wind, cloud, humidity, and rain odds, the most comfortable months at Cobb Mountain Area are June, September, and August. The best hours are usually 10 AM to 1 PM in June, 10 AM to 1 PM in September, and 8 AM to 11 AM in August. The warm season lasts about 3 months, from Jun 27 to Sep 26, when the average high is 77°F or warmer. Highs peak around Jul 8 at about 83°F.
What are the warmest and coldest months at Cobb Mountain Area?
July is the warmest month at Cobb Mountain Area, with an average high of 83°F. February is the coldest, with an average low of 37°F.
When does the fog burn off at Cobb Mountain Area?
Fog or low cloud covers Cobb Mountain Area in 46% of 5 AM hours in December, the foggiest month. It often lingers, and 24% of mid-afternoon hours are still foggy. June mornings are the least foggy (3%).
How much rain does Cobb Mountain Area get?
December is the wettest month (12.5 in.), out of about 55.1 in. a year. The rainy season runs from Oct 27 to Apr 22, when a day has at least a 25% chance of measurable rain. That stretch brings 89% of the year's rain. The 2025-26 rain year (Oct. 1 to Sep. 30) brought 56.9 in. of rain to Cobb Mountain Area, 103% of the 55.1 in. normal.
How does Cobb Mountain Area weather compare with Middletown?
Middletown sits 1,690 ft lower, 8 miles away. Its summer highs average 6°F warmer and its winter lows 1°F colder than Cobb Mountain Area.
What kind of place is Cobb Mountain Area?
Cobb Mountain, a volcanic peak in southern Lake County, is the highest summit in the Mayacamas Mountains. It looks down on The Geysers steam field to the west. The name also covers the small forested communities along Highway 175 on its flanks, including Cobb, Loch Lomond, Whispering Pines, and the old Hobergs resort area. Pine and mixed forest replace the oaks and chaparral of the valleys below. Much of the mountain burned in the 2015 Valley Fire.
What is Cobb Mountain Area weather like in November?
November at Cobb Mountain Area averages a high of 56°F and a low of 41°F, with 5.6 in. of rain over about 10 rainy days. About 27% of morning hours are foggy. Afternoon wind averages 7 mph.
More about Cobb Mountain Area 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.
- Lake County News, More snow expected; caution urged while driving (Jan. 22, 2008) (accessed 2026-10-27)
- Caltrans, Winter Driving Tips (accessed 2026-10-27)
- County of Lake, Lake Co Ready (accessed 2026-10-27)
- Friends of Boggs Mountain (accessed 2026-10-27)
- Lake County News, The Living Landscape: Cobb Mountain, crest of beauty (Dec. 15, 2019) (accessed 2026-10-27)
- Lake County News, Kincade fire update: Healdsburg and Windsor ordered to evacuate; Cobb evacuation warning remains (Oct. 26, 2019) (accessed 2026-10-27)
Rendered 2026-11-15T12:16:23.010Z.