Napa, CA weather in May
Expect mild, mostly dry weather in Napa in May, with highs near 77°F and lows near 50°F. Rain falls on about 4 days. Great for outdoor plans.
- Normal high
- 77°F
- Normal low
- 50°F
- Wet days
- 4
- 1.1 in total
- Muggy days
- 0
- dew point 65°F+
How May changes from start to finish
| May 1 | May 31 | |
|---|---|---|
| Normal high | 74°F | 79°F |
| Normal low | 47°F | 52°F |
| Chance of a wet day | 15% | 8% |
| Sunrise / sunset | 6:12 am / 8:00 pm | 5:47 am / 8:25 pm |
| Daylight | 13.8 h | 14.6 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Pacific Time).
A typical May day
- 6 am54°Fdew point 48°F
- 9 am65°Fdew point 48°F
- Noon74°Fdew point 48°F
- 3 pm76°Fdew point 49°F
- 6 pm69°Fdew point 49°F
- 9 pm59°Fdew point 49°F
NOAA hourly normals (local standard time) from Travis AFB (19 mi away); average wind 15 mph; clear or few clouds in 69% of daytime hours, mostly cloudy or overcast in 23%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F21 of 31
- Hot dayshigh 90°F or more3 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow4 of 31
- Notable rainat least 0.10 in2 of 31
- Freezing nightslow 32°F or below0 of 31
Average days per May, counted from daily records for each year 1991-2020.
Rain in May
Normal precipitation is 1.1 in; a dry May brings about 0.1 in and a wet one about 1.5 in (25th and 75th percentiles). About 1 day brings half an inch or more.
How May varies from year to year
- Warmest May, 1991-20202001: average high 85°F
- Coolest May1998: average high 68°F
- Wettest May1996: 3.7 in
- Driest May1992: no measurable precipitation
- Highest reading103°F (May 31, 2001)
- Lowest reading37°F (May 22, 2010)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
May compared with April and June
| April | May | June | |
|---|---|---|---|
| Normal high | 72°F | 77°F | 82°F |
| Normal low | 46°F | 50°F | 54°F |
| Wet days | 7 | 4 | 1 |
| Comfortable days | 19 | 21 | 13 |
| Daylight | 13.2 h | 14.3 h | 14.8 h |
Highs change by +5°F from April and +5°F into June.
Nearby alternatives in May
- Warmer: Stockton, CA59 mi · high 83°F · 3 wet days
- Cooler: San Francisco, CA37 mi · high 64°F · 4 wet days
How Napa ranks in May
- Normal high171st warmest of 378 cities; 30th of 60 in California
- Wet days69th driest of 378
- Comfortable days21st most of 339
What to pack for Napa in May
- Layers – afternoons near 77°F but nights near 50°F
- Sunglasses and sunscreen – about 14.3 hours of daylight and highs near 77°F
Heating and cooling
May has 99 heating degree days and 45 cooling degree days (base 65°F), 5% of the year's total heating and cooling demand.
Questions
How hot is Napa in May?
The normal high is 77°F and the normal low is 50°F. From 1991 to 2020 the hottest May reading was 103°F (May 31, 2001).
Does it rain a lot in Napa in May?
About 4 days in May have at least 0.01 in of precipitation, and the normal total is 1.1 in. The wettest May in 1991-2020 was in 1996 (3.7 in); the driest was in 1992, with no measurable precipitation.
Is May a good time to visit Napa?
May ranks 1st of 12 months on our comfort score for Napa (81 out of 100). It has about 21 comfortable days and about 3 days at 90°F or hotter. The best month is May.
Where the numbers come from
- Temperature, rain, snowfall and frost dates: Napa State Hospital (USC00046074), 1.8 mi SE of the city center, 35 ft . NOAA normals and daily records, 1991-2020.
- Snow depth: Fairfield (USC00042934), 12 mi E of the city center, 40 ft . NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour and cloud cover: Travis AFB (USW00023202), 19 mi E of the city center, 59 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Napa County Airport (724955-93227), 6.2 mi S of the city center, 15 ft . Hourly observations, 1991-2020.