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Mount Saint Helena

Mountain

Between Napa and Sonoma, Mount Saint Helena provides day‑hike trails across volcanic rock, with viewpoints used by walkers and vineyard visitors.

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In this guide

Mount Saint Helena essentials

Country: United States
Driest months: Jun-Aug
Pay in: Dollar ($)
Language: English

Mount Saint Helena at a Glance

About Mount Saint Helena

Mount Saint Helena is a volcanic peak in the Mayacamas Mountains of northern California with an elevation of 4,343 ft (1,324 m). It sits near the intersection of Napa, Sonoma and Lake counties and is a prominent landmark above Napa Valley.

Hikers use several trails that climb from the surrounding valleys to reach the summit and ridge. The summit area gives panoramic views over Napa Valley and the surrounding Mayacamas ridgeline, and southern slopes contain trailheads and picnic areas maintained by a state park.

The peak is part of the volcanic Mayacamas complex. The writer Robert Louis Stevenson stayed on Mount Saint Helena in 1880 and later wrote about his time there; the state park on the mountain is named after him.

Mount Saint Helena lies near the town of Calistoga in Napa Valley, about an hour to the north of the San Francisco Bay Area on clear-traffic days. The terrain around it is wooded upper slopes giving way to chaparral and oak lower down.

  • Best views: Summit visibility is best on clear days when you can see across Napa Valley and to distant peaks; mornings often have coastal fog while afternoons clear.
  • Seasonal conditions: Trails are seasonal and muddy in winter; springs bring wildflowers on lower slopes.

What to See#

  • Summit: Summit area at 4,343 ft (1,324 m) offers wide views across Napa Valley, Sonoma County and surrounding Mayacamas ridges.
  • Robert Louis Stevenson State Park: State park on the southern slopes that contains trailheads and picnic areas; main access for hikers approaching the summit from the Napa side.

Tips for Visiting Mount Saint Helena

  • Best time is early morning or late afternoon for cooler temperatures and the clearest summit views across Napa and Sonoma.
  • Access the mountain via Robert Louis Stevenson State Park - use the park's trailheads on the St. Helena/Calistoga side as the usual starting points and expect a steady, multi-hour hike to the summit.
  • Plan for a summit visit on a clear day: visibility can be extensive (Napa Valley, Sonoma hills, and distant peaks), so allow extra time for photography and return before afternoon winds pick up.
When to Go

Best Time to Visit Mount Saint Helena

Visit from spring through early autumn for the most reliable weather, clearer views and safer hiking conditions.

Late spring-early autumn (best time)
April-October · ~10-30°C (cooler at the summit)
Warm, mostly dry weather with long daylight and good visibility-best for hiking, vistas and wildflowers in spring.
Winter
November-March · ~0-12°C
Cold, wetter conditions with possible snow or ice at higher elevations; trails can be muddy or slippery and some routes may be impassable.

Weather & Climate near Mount Saint Helena

Climate

Mount Saint Helena's climate is classified as Warm-Summer Mediterranean - Warm-Summer Mediterranean climate with mild summers (peaking in August) and cold winters (coldest in March). Temperatures range from 1°C to 27°C. Abundant rainfall (1472 mm/year), wettest in January with a pronounced dry season.

Air Quality: AQI 34 Good
Temperature & Rainfall
Temperature Range
27°
Warmest Month
1°
Coldest Month
Monthly Conditions
Month Comfort Temp Feels Rain Sky Humidity Wind UV Daylight
January - 2° - 12° 5° 292 mm - - 2.5 m/s - -
February - 2° - 11° 4° 219 mm - - 2.8 m/s - -
March - 1° - 11° 4° 205 mm - - 2.9 m/s - -
April - 2° - 14° 6° 100 mm - - 3.1 m/s - -
May - 4° - 18° 11° 26 mm - - 3.1 m/s - -
June - 8° - 22° 15° 11 mm - - 3.2 m/s - -
July - 11° - 27° 19° 3 mm - - 2.8 m/s - -
August - 11° - 27° 19° 10 mm - - 2.6 m/s - -
September - 10° - 25° 18° 25 mm - - 2.4 m/s - -
October - 7° - 21° 14° 90 mm - - 2.2 m/s - -
November - 4° - 14° 8° 230 mm - - 2.3 m/s - -
December - 2° - 12° 5° 261 mm - - 2.3 m/s - -