Sintra weather in December

In December, Sintra sees average daytime highs of 15°C and overnight lows near 13°C, with 89 mm of rain across 10.6 wet days and about 9.3 hours of daylight. It is the 9th-warmest and 2nd-wettest month of the year here.

Day-to-day highs hold fairly steady near 15°C through the month. The sky is clear or mostly clear about 35% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 30 min at the start of December to 9 h 18 min by month's end. Set against the rest of the year, December is Sintra's 12th-clearest and 2nd-windiest month. For the whole year in context, see Sintra's year-round climate.

Daytime high
15°
9th warmest
Overnight low
13°
4th coldest
Rainfall
89 mm
10.6 wet days
Daylight
9 h 18 min
7:55 AM – 5:13 PM
Cloud cover
56%
12th clearest
Wind
24 km/h
2nd windiest
Solar energy
2.01 kWh/m²
Travel score
4.6
out of 10

Sintra is town seat of Sintra municipality, Lisbon District, Portugal.

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

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 15°C through the month.

A typical December day in Sintra reaches about 15°C in the afternoon and slips back to 13°C overnight — a 2°C spread between the day's warmth and the night's chill. On most days the high lands between 13°C and 17°C. Set against its neighbours, December runs about 1°C cooler than November and about 1°C warmer than January.

10°13°15°18°20°151015202531
Avg high (°C)Avg low (°C)
11614
21513
31513
41513
51513
61513
71513
81513
91513
101513
111513
121513
131513
141513
151513
161513
171513
181513
191513
201513
211513
221513
231513
241513
251513
261513
271513
281513
291513
301513
311513

Sintra weather by month

How December compares with the rest of the year at a glance. December is the 9th-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan14° / 12°8110.29.64.3
Feb14° / 12°608.210.54.3
Mar15° / 13°568.111.74.7
Apr15° / 14°507.8135.1
May17° / 15°405.414.16.1
Jun18° / 17°81.814.77.5
Jul19° / 18°20.614.48.2
Aug19° / 18°40.813.58.2
Sep19° / 18°273.812.37.5
Oct19° / 17°809116.3
Nov17° / 15°9510.69.95.3
Dec15° / 13°8910.69.34.6

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 35% of the time in December, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 14% of December, with mostly cloudy or overcast conditions the remaining 52%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14951
24951
34951
44951
54951
64951
74852
84753
94753
104852
114753
124753
134753
144654
154753
164753
174852
184753
194852
204951
214951
224951
234951
244951
254951
265050
275050
285050
295050
305050
315050

Chance of precipitation in December

Any precipitation

Sintra gets around 89 mm of rain over 10.6 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 34% and peaks near 37% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
136
235
335
435
534
634
733
833
933
1033
1133
1233
1333
1433
1533
1633
1733
1833
1934
2034
2134
2234
2335
2435
2535
2636
2736
2836
2937
3037
3137

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, December lands in the dry band about 81% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
178211
279210
379210
480200
580200
680200
780200
880200
980200
1080200
1181190
1281190
1381190
1481190
1580191
1681181
1781181
1881181
1982171
2082171
2182171
2282171
2382171
2482171
2582171
2681181
2781181
2881181
2981181
3082171
3183170

Wind in December

Winds average 24 km/h in December.

Across December, daily wind ranges from about 24 km/h on the calmest days to 25 km/h at its breeziest. It stays fairly steady from day to day.

0102030151015202531
Wind speed (km/h)Feels
124breezy
224breezy
324breezy
424breezy
524breezy
624breezy
724breezy
824breezy
924breezy
1024breezy
1124breezy
1224breezy
1324breezy
1424breezy
1524breezy
1624breezy
1724breezy
1824breezy
1925breezy
2025breezy
2125breezy
2225breezy
2325breezy
2425breezy
2525breezy
2624breezy
2724breezy
2824breezy
2924breezy
3024breezy
3124breezy

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 30 min at the start of December to 9 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 12 minutes over December. Sunrise moves from 7:43 AM to 8:01 AM, and sunset from 5:12 PM to 5:20 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.57:435:12
29.57:445:12
39.47:455:11
49.47:465:11
59.47:465:11
69.47:475:11
79.47:485:11
89.47:495:11
99.47:505:11
109.37:515:11
119.37:515:11
129.37:525:12
139.37:535:12
149.37:535:12
159.37:545:12
169.37:555:13
179.37:555:13
189.37:565:13
199.37:575:14
209.37:575:14
219.37:585:14
229.37:585:15
239.37:595:15
249.37:595:16
259.37:595:16
269.38:005:17
279.38:005:18
289.38:005:18
299.38:015:19
309.38:015:20
319.38:015:20

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.01 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.01 kWh/m² to a high of 7.51 kWh/m² in July across the year — December's 2.01 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.1Moderate
22.1Moderate
32.1Moderate
42.1Moderate
52.1Moderate
62.1Moderate
72.0Moderate
82.0Moderate
92.0Moderate
102.0Moderate
112.0Moderate
122.0Moderate
132.0Moderate
142.0Dim
152.0Dim
162.0Dim
172.0Dim
182.0Dim
192.0Dim
202.0Dim
212.0Dim
222.0Dim
232.0Moderate
242.0Moderate
252.0Moderate
262.0Moderate
272.0Moderate
282.0Moderate
292.0Moderate
302.0Moderate
312.0Moderate
Planning a trip in December

Hazard calendar for Sintra

In seasonPeak

In December, Sintra sits inside its rainy season season. The full year is below, with each hazard's peak months called out.

Sintra's rainy season runs October–April, when most of the year's rain falls.

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

Is December a good time to visit Sintra?

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

4.6
Sightseeing
10th-best month of the year
0.1
Beach & pool
9th-best month of the year

December is a reasonable time to visit Sintra for sightseeing.

What to pack for Sintra in December

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

In December, Sintra sees daytime highs around 15°C and nights near 13°C. Worth packing: a warm layer, rain gear and a windbreaker. About 11 days see rain.

a warm layerrain geara windbreaker

Sea temperature near Sintra in December

The nearest coast averages about 16°C in December — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 20 km away) is warmest in September at about 19°C and coldest in February near 15°C.

The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.

14°16°18°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°C)Comfort
Jan15Cool
Feb15Bracing
Mar15Bracing
Apr15Cool
May16Cool
Jun18Cool
Jul18Cool
Aug19Cool
Sep19Cool
Oct18Cool
Nov17Cool
Dec16Cool

UV index in Sintra in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 2. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Sintra peaks around July 15 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateJul 15UV 9Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar6High
Apr8Very high
May7Very high
Jun9Very high
Jul9Very high
Aug9Very high
Sep6High
Oct5High
Nov3Moderate
Dec2Low
Location & terrain

Where is Sintra?

Sintra sits at 38.8°N, 9.4°W, 197 m above sea level, in Portugal. The nearest listed city is Algueirão, 3.0 km away.

Topography around Sintra

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

Within 3 km, the terrain around Sintra has significant variations in elevation — a maximum elevation change of 460 m around an average of 198 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 513 m; within 80 km, large variations in elevation — a maximum elevation change of 651 m.

The land around Sintra is covered by trees (49%), grassland (27%) and artificial surfaces (22%) within 3 km, water (28%), grassland (27%) and trees (24%) within 16 km, and water (47%) and grassland (24%) within 80 km.

3 km
460 m
16 km
513 m
80 km
651 m
treesshrubsgrasslandcroplandartificial surfaceswater
December weather nearby: Algueirão 3.0 km · Rio de Mouro 6.0 km · Cacém 8.0 km · Alcabideche 8.0 km · Massamá 10 km · Belas 10 km · Estoril 11 km · Monte Estoril 11 km

Portugal travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / E / F
230 V · 50 Hz
Prices
≈ 60% of US
price level, 2025
GDP per capita
$32,082
2025
Happiness
6.0 / 10
World Happiness, 2025
Safe drinking water
95%
of population, 2024
Homicide rate
0.7
per 100k, 2022
Road deaths
8.2
per 100k/yr, 2019
Income group
High
World Bank
English
Very high
EF EPI 612
Religion
Catholic 68%not applicable 13%no religion 12%no response 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 Sintra (38.801°, -9.3783°, elevation 197 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. 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).