Best time to visit Napa
Re-score for me — drag the dial — every chart on the page recolours live for your heat limit 27°C
Default 27 °C is the upper edge of the Holiday Climate Index "ideal comfort" band (Scott, Rutty, Amelung & Tang, 2016). Above this, most warm-tourism travellers report measurable discomfort.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
Greyed factors are scored normally — extreme heat overrides them, so a clear sky or low rain can't lift the period.
How is this scored? HCI / Steadman / CCI gate — full methodology and citations below.
Compare with another destination
Add as many as you like — stacked below the main strips above. Each row is just the recent-window score strip and (for beach destinations) sea-temperature strip.
Tours in Napa
6 top-rated tours via Viator. Booking links earn this site a commission at no cost to you. Map locations are approximate (centred on Napa).
- 1
Fabulous Private Wine Tour of Napa & Sonoma: 2 to 5 People - 2
#1 Sonoma Walking Food, Wine Tasting & History Tour (Public Tour) - 3
Napa Valley Small Group Winery Tour - 4
Private Vacation Photoshoot with Photographer in Napa - 5
Sonoma Plaza Food and Wine Pairing Tour - 6
Safari West Sonoma Adventure Tour
Last refreshed 2026-05-25.
Similar climatesGranada91% · Los Angeles88% · Petra88%
Other destinations with the most-alike year-round climate to Napa (apparent temperature, rain hours, sunshine — matched within the same trip-profile). The ±N chip compares each match's typical score for the current month against Napa's. Based on the 2020-2024 climatology, not this year's actual weather.
Month-by-month
| Month | Temp °C | Feels °C | Rain days | Rain h | Rain h/day | Humidity | Wind km/h | Sun h | UV | Interest | Score |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Jan | 5–15 | 13 | 9 | 119 | 13.2 | 70% | 13 | 153 | 2 | Quiet | 7 |
| Feb | 5–17 | 15 | 6 | 74 | 12.3 | 58% | 14 | 189 | 3 | Quiet | 8 |
| Mar | 6–17 | 15 | 10 | 139 | 13.9 | 59% | 15 | 208 | 4 | Quiet | 7 |
| Apr | 7–21 | 19 | 3 | 39 | 13.0 | 52% | 15 | 260 | 6 | Quiet | 10 |
| May | 10–25 | 24 | 3 | 32 | 10.7 | 45% | 17 | 296 | 8 | Quiet | 10 |
| Jun | 13–28 | 27 | 1 | 6 | 6.0 | 41% | 17 | 300 | 9 | Quiet | 10 |
| Jul | 13–30 | 31 | 0 | 1 | — | 42% | 15 | 306 | 10 | Quiet | 7 |
| Aug | 14–31 | 31 | 0 | 5 | — | 42% | 15 | 289 | 9 | Peak | 7 |
| Sep | 14–30 | 30 | 1 | 14 | 14.0 | 42% | 14 | 254 | 6 | Busy | 8 |
| Oct | 11–26 | 25 | 3 | 32 | 10.7 | 43% | 13 | 224 | 4 | Quiet | 10 |
| Nov | 6–18 | 17 | 6 | 68 | 11.3 | 55% | 12 | 188 | 2 | Moderate | 8 |
| Dec | 5–14 | 13 | 12 | 145 | 12.1 | 72% | 11 | 146 | 2 | Moderate | 6 |
UV Index in Napa by Month
UV index in Napa peaks at 10 (very high) in July, dropping to 2 (low) in December. June, July, August reach very high or extreme levels — apply SPF 50+, wear a hat and protective clothing, and limit direct sun between 11:00 and 17:00.
Best months in detail
May
10/1010–25°C (feels 24°C) · 3 rain days (32h) · 296 sun hours · 45% humidity · Quiet crowd · UV 8 (high) · sunniest 1 in 10 days reach 9 (very high)
April
10/107–21°C (feels 19°C) · 3 rain days (39h) · 260 sun hours · 52% humidity · Quiet crowd · UV 6 (high) · sunniest 1 in 10 days reach 8 (high)
October
10/1011–26°C · 3 rain days (32h) · 224 sun hours · 43% humidity · Quiet crowd · UV 4 (moderate)
Every month
Show the other 9 months in detail
January
7/105–15°C (feels 13°C) · 9 rain days (119h) · 153 sun hours · 70% humidity · Quiet crowd · UV 2 (low)
February
8/105–17°C (feels 15°C) · 6 rain days (74h) · 189 sun hours · 58% humidity · Quiet crowd · UV 3 (low) · sunniest 1 in 10 days reach 4 (moderate)
March
7/106–17°C (feels 15°C) · 10 rain days (139h) · 208 sun hours · 59% humidity · Quiet crowd · UV 4 (moderate) · sunniest 1 in 10 days reach 6 (high)
June
10/1013–28°C · 1 rain days (6h) · 300 sun hours · 41% humidity · Quiet crowd · UV 9 (very high)
July
7/1013–30°C · 0 rain days (1h) · 306 sun hours · 42% humidity · Quiet crowd · UV 10 (very high)
August
7/1014–31°C · 0 rain days (5h) · 289 sun hours · 42% humidity · Peak crowd · UV 9 (very high)
September
8/1014–30°C · 1 rain days (14h) · 254 sun hours · 42% humidity · Busy crowd · UV 6 (high)
November
8/106–18°C (feels 17°C) · 6 rain days (68h) · 188 sun hours · 55% humidity · Moderate crowd · UV 2 (low) · sunniest 1 in 10 days reach 3 (moderate)
December
6/105–14°C (feels 13°C) · 12 rain days (145h) · 146 sun hours · 72% humidity · Moderate crowd · UV 2 (low)
Frequently asked questions about visiting Napa
When is the best time to visit Napa?
May is the highest-scoring month (10/10 on the Holiday Climate Index). Typical conditions: 10–25°C (3 rainy days). The top three months by score are May, April, October.
What is the worst time to visit Napa?
December is the lowest-scoring month (6/10). Typical conditions: 5–14°C (12 rainy days).
Is Napa too hot in summer?
2 months (July, August) trip the heat deal-breaker in our scoring: apparent temperature crosses the comfort cap, so even with clear skies and low rain the score is held down. Plan around it if heat tolerance is low.
When are crowds lowest in Napa?
Search-interest seasonality (Google Trends 2021-2025) is lowest in February and peaks in August. Interest tracks both in-trip visitors and lead-time planners, so treat it as a "destination is on people's minds" signal rather than literal arrivals.
Which months in Napa have good weather but fewer tourists?
April (climate 10/10, crowd index 4) and May (climate 10/10, crowd index 14) — shoulder months with above-average climate and below-median search-interest. Often the best value-for-weather trade.
What is the UV index in Napa by month?
UV peaks at 10 (very high) in July and is lowest in December at 2 (low). Monthly peak values: Jan 2, Feb 3, Mar 4, Apr 6, May 8, Jun 9, Jul 10, Aug 9, Sep 6, Oct 4, Nov 2, Dec 2. June, July, August reach very high or extreme levels — apply SPF 50+, wear a hat and protective clothing, and limit direct sun between 11:00 and 17:00.
What is the UV index in Napa in July?
July is the peak UV month in Napa, with a daily-peak UV index of 10 (very high). At this level, sunburn can occur in under 20 minutes on unprotected fair skin. Apply SPF 50+, wear protective clothing and a hat, and avoid direct midday sun (11:00–17:00).
How high can UV get in Napa on the sunniest days?
Most days look like the monthly average, but on the sunniest ~1 in 10 days UV climbs higher than the mean suggests. May is the worst case: typical days average UV 8 (high), but the top 10% of days reach UV 9 (very high) — and even higher. Months where the sunniest days routinely exceed the typical reading: February, March, April, May, November. Plan sun protection for the worst case, not the average.
Is air quality in Napa bad for travelers?
PM2.5 (fine-particle pollution) exceeds the WHO sensitive-group guideline (15 µg/m³) in 1 month: December. The worst month is December with a typical-day mean of 9 µg/m³ (fair); on the worst 10% of days PM2.5 reaches 18 µg/m³ (unhealthy for sensitive) and higher. People with asthma, heart conditions, or sensitive children may want to avoid these months or limit outdoor activity. Source: CAMS via Open-Meteo.