San Mateo, CA weather in May
San Mateo is mild and mostly dry in May: highs average 68°F and nights drop to about 52°F. Expect about 3 wet days. A great month for outdoor plans.
- Normal high
- 68°F
- Normal low
- 52°F
- Wet days
- 3
- 0.5 in total
- Muggy days
- 0
- dew point 65°F+
How May changes from start to finish
| May 1 | May 31 | |
|---|---|---|
| Normal high | 67°F | 70°F |
| Normal low | 50°F | 53°F |
| Chance of a wet day | 13% | 8% |
| Sunrise / sunset | 6:13 am / 7:59 pm | 5:49 am / 8:24 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 am60°Fdew point 49°F
- Noon65°Fdew point 49°F
- 3 pm65°Fdew point 48°F
- 6 pm60°Fdew point 48°F
- 9 pm56°Fdew point 48°F
NOAA hourly normals (local standard time) from San Francisco Intl Airport (5 mi away); average wind 14 mph; clear or few clouds in 44% of daytime hours, mostly cloudy or overcast in 34%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F18 of 31
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph1 of 31
- Hot dayshigh 90°F or more0 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow3 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 0.5 in; a dry May brings about 0.01 in and a wet one about 0.6 in (25th and 75th percentiles). Days with half an inch or more are rare.
How May varies from year to year
- Warmest May, 1991-20201997: average high 73°F
- Coolest May1999: average high 63°F
- Wettest May1998: 2.4 in
- Driest May1992: no measurable precipitation
- Highest reading96°F (May 15, 2008)
- Lowest reading44°F (May 1, 2008)
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 | 66°F | 68°F | 72°F |
| Normal low | 49°F | 52°F | 54°F |
| Wet days | 6 | 3 | 1 |
| Comfortable days | 12 | 18 | 23 |
| Daylight | 13.2 h | 14.2 h | 14.7 h |
Highs change by +2°F from April and +4°F into June.
Nearby alternatives in May
- Warmer: San Jose, CA28 mi · high 74°F · 3 wet days
- Cooler: South Lake Tahoe, CA158 mi · high 62°F · 5 wet days
How San Mateo ranks in May
- Normal high297th warmest of 378 cities; 53rd of 60 in California
- Wet days63rd driest of 378
- Comfortable days34th most of 339
Heating and cooling
May has 170 heating degree days and 14 cooling degree days (base 65°F), 7% of the year's total heating and cooling demand.
Questions
How cold is San Mateo in May?
The normal high is 68°F and the normal low is 52°F. From 1991 to 2020 the coldest May reading was 44°F (May 1, 2008).
Does it rain a lot in San Mateo in May?
About 3 days in May have at least 0.01 in of precipitation, and the normal total is 0.5 in. The wettest May in 1991-2020 was in 1998 (2.4 in); the driest was in 1992, with no measurable precipitation.
Is May a good time to visit San Mateo?
May ranks 5th of 12 months on our comfort score for San Mateo (79 out of 100). It has about 18 comfortable days. The best months are July and August.
Where the numbers come from
- Temperature, rain, frost dates, humidity and wind by hour and cloud cover: San Francisco Intl Airport (USW00023234), 4.5 mi NNW of the city center, 8 ft . NOAA normals and daily records, 1991-2020.
- Snowfall and snow depth: Redwood City (USC00047339), 7.6 mi SE of the city center, 31 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: San Francisco International Airport (724940-23234), 4.5 mi NNW of the city center, 10 ft . Hourly observations, 1991-2020.