Millbrae weather in May

In May, Millbrae sees average daytime highs of 59°F and overnight lows near 52°F, with 0.7 in of rain across 3.1 wet days and about 14 hours of daylight. It is the 7th-warmest and 8th-wettest month of the year here.

Day-to-day highs hold fairly steady near 59°F through the month. The sky is clear or mostly clear about 45% of the time in May, and the air most often feels dry.

Daylight stretches from about 13 h 30 min at the start of May to 14 h 24 min by month's end. Set against the rest of the year, May is Millbrae's 6th-clearest and 2nd-windiest month. For the whole year in context, see Millbrae's year-round climate.

Daytime high
59°
7th warmest
Overnight low
52°
7th coldest
Rainfall
0.7 in
3.1 wet days
Daylight
14 hours
5:05 AM – 7:06 PM
Cloud cover
47%
6th clearest
Wind
10 mph
2nd windiest
Solar energy
7.06 kWh/m²
Travel score
5.5
out of 10

Millbrae is city located in northern San Mateo County, California, United States.

Density
2,701/km²
people per km²
Founded
1948

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 59°F through the month.

A typical May day in Millbrae reaches about 59°F in the afternoon and slips back to 52°F overnight — a 7°F spread between the day's warmth and the night's chill. On most days the high lands between 55°F and 64°F. Set against its neighbours, May runs about 1°F warmer than April and about 2°F cooler than June.

40°50°60°70°151015202531
Avg high (°F)Avg low (°F)
15951
25951
35951
45951
55952
65952
75952
85952
95952
105952
115952
125952
135952
145952
155952
165952
175952
185952
195952
205952
215953
225953
235953
245953
255953
266053
276053
286053
296053
306053
316053

Millbrae weather by month

How May compares with the rest of the year at a glance. May is the 7th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan55° / 48°4.0109.73.6
Feb56° / 49°4.29.410.63.8
Mar57° / 50°3.19.311.74.2
Apr58° / 51°1.55.312.94.8
May59° / 52°0.73.1145.5
Jun61° / 54°0.20.814.56.5
Jul63° / 55°0.00.114.37.1
Aug64° / 57°0.00.113.47.5
Sep65° / 57°0.10.512.37.7
Oct64° / 55°0.93.1117.1
Nov59° / 52°2.16.2105.1
Dec56° / 49°4.09.89.53.7

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 45% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 18% of May, with mostly cloudy or overcast conditions the remaining 37%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16436
26337
36337
46337
56337
66238
76238
86139
96139
106139
116040
126139
136139
146238
156238
166337
176337
186337
196337
206337
216436
226436
236436
246436
256535
266535
276535
286535
296535
306535
316535

Chance of precipitation in May

Any precipitation

Millbrae gets around 0.7 in of rain over 3.1 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 10% and peaks near 12% on the wettest days.

0%10%20%30%151015202531
Rain chance (%)
112
211
311
411
510
610
710
810
910
1010
1110
1210
1310
1410
1510
1610
1710
1810
1910
2010
2110
2210
2310
249
259
268
278
287
297
307
317

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

Most of May feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, May lands in the dry band about 96% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1982
2982
3982
4982
5982
6982
7973
8973
9973
10973
11973
12964
13964
14964
15964
16955
17955
18955
19955
20946
21946
22946
23946
24946
25946
26946
27946
28946
29946
30946
31946

Wind in May

Winds average 10 mph in May.

Across May, daily wind ranges from about 10 mph on the calmest days to 10 mph at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (mph)Feels
110light breeze
210light breeze
310light breeze
410light breeze
510light breeze
610light breeze
710light breeze
810light breeze
910light breeze
1010light breeze
1110light breeze
1210light breeze
1310light breeze
1410light breeze
1510light breeze
1610light breeze
1710light breeze
1810light breeze
1910light breeze
2010light breeze
2110light breeze
2210light breeze
2310light breeze
2410light breeze
2510light breeze
2610light breeze
2710light breeze
2810light breeze
2910light breeze
3010light breeze
3110light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 30 min at the start of May to 14 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 54 minutes over May. Sunrise moves from 5:21 AM to 4:56 AM, and sunset from 6:53 PM to 7:18 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.55:216:53
213.65:206:54
313.65:186:55
413.65:176:55
513.75:166:56
613.75:156:57
713.75:146:58
813.85:136:59
913.85:127:00
1013.85:117:01
1113.95:107:02
1213.95:097:03
1313.95:087:04
1414.05:077:05
1514.05:067:05
1614.05:057:06
1714.05:047:07
1814.15:047:08
1914.15:037:09
2014.15:027:10
2114.25:017:11
2214.25:017:11
2314.25:007:12
2414.24:597:13
2514.34:597:14
2614.34:587:15
2714.34:587:15
2814.34:577:16
2914.34:567:17
3014.44:567:18
3114.44:567:18

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 7.06 kWh/m².

For context, solar energy here swings from a low near 2.25 kWh/m² to a high of 7.64 kWh/m² in June across the year — May's 7.06 kWh/m² sits near the top of that range.

02468151015202531
Solar energy (kWh/m²)Level
16.8Intense
26.8Intense
36.9Intense
46.9Intense
56.9Intense
66.9Intense
77.0Intense
87.0Intense
97.0Intense
107.0Intense
117.0Intense
127.0Intense
137.0Intense
147.1Intense
157.1Intense
167.1Intense
177.1Intense
187.1Intense
197.1Intense
207.1Intense
217.1Intense
227.2Intense
237.2Intense
247.2Intense
257.2Intense
267.2Intense
277.2Intense
287.3Intense
297.3Intense
307.3Intense
317.3Intense
Planning a trip in May

Hazard calendar for Millbrae

In seasonPeak

None of Millbrae's seasonal hazards are active in May. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Millbrae's rainy season runs November–March, when most of the year's rain falls.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is May a good time to visit Millbrae?

Our two travel scores rate May for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

5.5
Sightseeing
6th-best month of the year
0.1
Beach & pool
7th-best month of the year

May is a reasonable time to visit Millbrae for sightseeing.

What to pack for Millbrae in May

From May's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In May, Millbrae sees daytime highs around 59°F and nights near 52°F. Pack sun protection. Worth having: a warm layer. About 3 days see rain.

sun protectiona warm layer

Sea temperature near Millbrae in May

The nearest coast averages about 53°F in May — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 13 mi away) is warmest in September at about 58°F and coldest in April near 53°F.

The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.

52°54°56°58°60°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°F)Comfort
Jan53Bracing
Feb54Bracing
Mar54Bracing
Apr53Bracing
May53Bracing
Jun54Bracing
Jul56Bracing
Aug58Bracing
Sep58Bracing
Oct57Bracing
Nov56Bracing
Dec54Bracing

UV index in Millbrae in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Millbrae peaks around June 23 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 2 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJun 23UV 10Dec 15UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5Moderate
Apr6High
May8Very high
Jun10Extreme
Jul10Extreme
Aug10Very high
Sep6High
Oct5High
Nov2Moderate
Dec2Moderate

Air quality in Millbrae in May

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where May falls, not just the annual average.

Air quality in Millbrae is worst in August — around 25 µg/m³ PM2.5 (moderate), about 2.5× the cleanest month (June, 10 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateAug 1824 µg/m³Jun 1110 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb18Moderate
Mar16Moderate
Apr12Moderate
May10Good
Jun10Good
Jul11Good
Aug25Moderate
Sep17Moderate
Oct20Moderate
Nov18Moderate
Dec13Moderate
Location & terrain

Where is Millbrae?

Millbrae sits at 37.6°N, 122.4°W, 33 ft above sea level, in United States. The nearest listed city is Burlingame, 1.2 mi away.

Topography around Millbrae

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Millbrae.

Within 2 miles, the terrain around Millbrae has only modest variations in elevation — a maximum elevation change of 663 ft around an average of 141 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,005 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,452 ft.

The land around Millbrae is covered by artificial surfaces (56%) and trees (22%) within 2 miles, water (44%), trees (27%) and artificial surfaces (21%) within 10 miles, and water (42%), trees (22%) and grassland (21%) within 50 miles.

2 miles
663 ft
10 miles
2,005 ft
50 miles
4,452 ft
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
May weather nearby: Burlingame 1.2 mi · San Bruno 2.5 mi · South San Francisco 3.7 mi · San Mateo 4.3 mi · Pacifica 5.6 mi · Foster City 6.8 mi · Belmont 8.1 mi · Visitacion Valley 8.1 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Millbrae (37.5986°, -122.3872°, elevation 33 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).