San Mateo weather in December

In December, San Mateo sees average daytime highs of 27°C and overnight lows near 21°C, with 239 mm of rain across 20 wet days and about 11 hours of daylight. It is the 11th-warmest and 5th-wettest month of the year here.

Day-to-day highs hold fairly steady near 27°C through the month. The sky is clear or mostly clear about 14% of the time in December, and the air most often feels muggy.

Daylight stretches from about 11 h 06 min at the start of December to 11 hours by month's end. Set against the rest of the year, December is San Mateo's 9th-clearest and 1st-windiest month. For the whole year in context, see San Mateo's year-round climate.

Daytime high
27°
11th warmest
Overnight low
21°
3rd coldest
Rainfall
239 mm
20 wet days
Daylight
11 hours
6:20 AM – 5:20 PM
Cloud cover
75%
9th clearest
Wind
6 km/h
1st windiest
Solar energy
2.69 kWh/m²
Travel score
5.0
out of 10

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 27°C through the month.

A typical December day in San Mateo reaches about 27°C in the afternoon and slips back to 21°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 24°C and 29°C. Set against its neighbours, December runs about 2°C cooler than November and on par with January.

15°20°25°30°151015202531
Avg high (°C)Avg low (°C)
12721
22721
32721
42721
52721
62721
72721
82721
92721
102721
112721
122721
132721
142721
152721
162721
172621
182621
192621
202621
212621
222621
232620
242620
252620
262620
272620
282620
292620
302620
312620

How December really feels in San Mateo

Once humidity and wind are folded in, December averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

December sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

San Mateo weather by month

How December compares with the rest of the year at a glance. December is the 11th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan26° / 20°11916.311.15.5
Feb27° / 20°9413.711.45.7
Mar29° / 21°9414.211.95.3
Apr31° / 22°9513.812.44.1
May33° / 23°27420.612.82.8
Jun33° / 24°22922.4132.4
Jul32° / 24°31826.112.92.5
Aug32° / 24°32326.412.62.5
Sep31° / 24°2942412.12.9
Oct30° / 23°22419.611.63.9
Nov28° / 22°20018.611.24.6
Dec27° / 21°23920115.0

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 14% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 15% of December, with mostly cloudy or overcast conditions the remaining 72%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13367
23268
33268
43169
53169
63169
73169
83070
93070
103070
113070
123070
132971
142971
152971
162971
172872
182872
192872
202872
212773
222773
232575
242575
252575
262575
272575
282674
292773
302674
312773

Chance of precipitation in December

Any precipitation

San Mateo gets around 239 mm of rain over 20 wet days in December. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 64% and peaks near 67% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
165
265
366
466
566
667
767
867
967
1067
1167
1267
1366
1466
1565
1665
1764
1864
1963
2063
2163
2262
2362
2461
2561
2660
2759
2858
2958
3057
3156

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, December lands in the muggy band about 47% of days. Sticky, muggy-or-worse air turns up on roughly 92% of them.

0%25%50%75%100%151015202531
Humid (%)Muggy (%)Oppressive (%)
143660
243858
343957
444155
544155
644254
744254
844254
944254
1044254
1154352
1254352
1354451
1464550
1564549
1674647
1774746
1884745
1984843
2094942
21105040
22105238
23115237
24125335
25125434
26135532
27135631
28135730
29145729
30145828
31145828

Wind in December

Winds average 6 km/h in December, the windiest month of the year.

Across December, daily wind ranges from about 6 km/h on the calmest days to 6 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (km/h)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm
316calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 11 h 06 min at the start of December to 11 hours by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 6 minutes over December. Sunrise moves from 6:11 AM to 6:27 AM, and sunset from 5:15 PM to 5:27 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.16:115:15
211.16:125:16
311.16:135:16
411.06:135:16
511.06:145:16
611.06:145:16
711.06:155:17
811.06:155:17
911.06:165:17
1011.06:175:18
1111.06:175:18
1211.06:185:18
1311.06:185:19
1411.06:195:19
1511.06:195:19
1611.06:205:20
1711.06:205:20
1811.06:215:21
1911.06:215:21
2011.06:225:21
2111.06:225:22
2211.06:235:22
2311.06:235:23
2411.06:245:23
2511.06:245:24
2611.06:255:24
2711.06:255:25
2811.06:255:25
2911.06:265:26
3011.06:265:26
3111.06:275:27

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.69 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.69 kWh/m² to a high of 5.9 kWh/m² in April across the year — December's 2.69 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
13.0Moderate
22.9Moderate
32.9Moderate
42.9Moderate
52.9Moderate
62.8Moderate
72.8Moderate
82.8Moderate
92.8Moderate
102.7Moderate
112.7Moderate
122.7Moderate
132.7Moderate
142.7Moderate
152.7Moderate
162.7Moderate
172.7Moderate
182.7Moderate
192.7Moderate
202.7Moderate
212.7Moderate
222.7Moderate
232.7Moderate
242.7Moderate
252.7Moderate
262.8Moderate
272.8Moderate
282.8Moderate
292.8Moderate
302.9Moderate
312.9Moderate
Planning a trip in December

Is December a good time to visit San Mateo?

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

5.0
Sightseeing
4th-best month of the year
5.0
Beach & pool
7th-best month of the year

December is a reasonable time to visit San Mateo for sightseeing.

What to pack for San Mateo in December

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

In December, San Mateo sees daytime highs around 27°C and nights near 21°C. Pack rain gear. Worth having: light clothes. About 20 days see rain.

rain gearlight clothes

UV index in San Mateo in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in San Mateo peaks around August 19 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 11 at about 8 (very high).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecVery highExtremeVery highAug 19UV 14Dec 11UV 8
UV index (midday)Level
Jan9Very high
Feb11Extreme
Mar12Extreme
Apr13Extreme
May13Extreme
Jun13Extreme
Jul12Extreme
Aug14Extreme
Sep13Extreme
Oct10Extreme
Nov8Very high
Dec8Very high

Air quality in San Mateo in December

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in San Mateo is worst in April — around 20 µg/m³ PM2.5 (moderate), and holds fairly steady the rest of the year.

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateApr 1120 µg/m³Jun 2313 µg/m³
PM2.5 (µg/m³)Level
Jan16Moderate
Feb16Moderate
Mar19Moderate
Apr20Moderate
May15Moderate
Jun13Moderate
Jul13Moderate
Aug14Moderate
Sep16Moderate
Oct15Moderate
Nov15Moderate
Dec14Moderate
Location & terrain

Where is San Mateo?

San Mateo sits at 16.9°N, 121.6°E, 82 m above sea level, in Philippines. The nearest listed city is Ramon, 12 km away.

Topography around San Mateo

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of San Mateo.

Within 3 km, the terrain around San Mateo has only modest variations in elevation — a maximum elevation change of 19 m around an average of 78 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 402 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,889 m.

The land around San Mateo is covered by cropland (78%) within 3 km, cropland (70%) and trees (22%) within 16 km, and trees (70%) and cropland (22%) within 80 km.

3 km
19 m
16 km
402 m
80 km
2,889 m
treesgrasslandcroplandartificial surfaceswater
December weather nearby: Ramon 12 km · Alicia 16 km · Santiago 22 km · Roxas 27 km · Diadi 30 km · Ilagan 44 km · Aglipay 44 km · Lagawe 51 km

Philippines travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type A / B / C
230 V · 60 Hz
Prices
≈ 33% of US
price level, 2025
GDP per capita
$4,171
2025
Happiness
6.2 / 10
World Happiness, 2025
Safe drinking water
48%
of population, 2024
Homicide rate
4.3
per 100k, 2023
Road deaths
12
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
High
EF EPI 569
Religion
Roman Catholic 79%other 8%Muslim 6%other Christian 4%

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 San Mateo (16.8821°, 121.5869°, elevation 82 m), 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. 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).