Early autumn · Weather & things to do
Napa in September
Napa edges cooler than August, with highs of 85°F (30°C), lows of 54°F (12°C) and about 0.1 in (3 mm) of rain.
September opens the best stretch on our comfort score, at 90/100 (5th of 12).
- Avg high
- 85°F (30°C)
- Avg low
- 54°F (12°C)
- Rain
- 0.1 in (3 mm)
- Humidity
- 47%
- Cloud cover
- 21%
- Daylight
- ~12 h 14 min
- Comfort score
- 90/100 · Great
What September feels like
Days are warm, averaging 85°F (30°C), easy weather for being outside from morning to evening.
Mornings start much cooler: lows average 54°F (12°C), about 17°C (31°F) below the afternoon high.
It's one of the drier stretches, with only about 0.1 in (3 mm) of rain.
Sunny spells dominate: cloud cover averages 21%.
Plan around September
September is one of Napa's best months on the climate data.
- Opens the best-scoring stretch on our comfort score: April – June and September – November.
- Comfort improves from 83/100 in August to 90/100.
- September sits inside the Apr – Oct window our California Wine Country route recommends.
What to pack for September
- Light, breathable clotheshighs average 85°F
- Sunscreen, sunglasses and a hathigh UV on clear days
- A warm layer for eveningslows near 54°F
- Comfortable walking shoesmost places below are best reached on foot or with short walks
What to do in Napa in September
September is good outdoor weather here, so these picks lean toward the open air.
Napa Valley Wine Train
Restored vintage railcars serving multi-course meals on a 36-mile round trip.
Schramsberg Vineyards
Guided tour of hand-dug caves at a historic sparkling wine estate.
Bouchon Bakery
Thomas Keller's Yountville bakery for croissants and coffee.
Mustards Grill
Highway 29 roadhouse serving wine-country comfort food since 1983.
Domaine Carneros
Chateau-style sparkling wine house with a terrace over the vineyards.
Why now September scores 90/100 for comfort, good conditions for being outside.
Nearby in September
- Sonoma in September~18 mi · highs 88°F, 0.1 in rain · 2°C (3°F) warmer by day, about as wet
- Healdsburg in September~33 mi · highs 76°F, 0.2 in rain · 5°C (10°F) cooler by day, about as wet
- Old Sacramento Waterfront in September~42 mi · highs 91°F, 0.2 in rain · 3°C (6°F) warmer by day, about as wet
- San Francisco in September~51 mi · highs 74°F, 0.2 in rain · 6°C (11°F) cooler by day, about as wet
NASA POWER 2001–2025 monthly averages on a ~50 km grid. Comfort scores weigh temperature, rain, humidity and cloud: see how we score each month. Check a forecast before you go.
Napa in September: quick answers
Is September a good time to visit Napa?
Yes. On the climate data it's one of the best months, scoring 90/100. Expect highs of 85°F (30°C) and 0.1 in (3 mm) of rain. September is inside the Apr – Oct window our California Wine Country route recommends.
How hot is Napa in September?
Average highs are 85°F (30°C) and average lows 54°F (12°C), making it the 3rd-warmest month by daytime highs.
Does it rain a lot in Napa in September?
Not much: about 0.1 in (3 mm) of rain falls across September on average, the 3rd-driest month of the year. The annual total is about 27.1 in (689 mm).
What should I pack for Napa in September?
Bring light, breathable clothes (highs average 85°F), sunscreen, sunglasses and a hat (high UV on clear days), a warm layer for evenings (lows near 54°F) and comfortable walking shoes (most places below are best reached on foot or with short walks).
Routes in season in September
- California Wine Country Apr – Oct
Planning Napa in September?
Share this September plan with your group, poll everyone on dates and keep the packing list in one place.