Castro weather in December

In December, Castro sees average daytime highs of 18°C and overnight lows near 9°C, with 82 mm of rain across 12.6 wet days and about 15.1 hours of daylight. It is the 4th-warmest and 10th-wettest month of the year here.

Day-to-day highs hold fairly steady near 18°C through the month. The sky is clear or mostly clear about 16% of the time in December, and the air most often feels dry.

Daylight stretches from about 14 h 54 min at the start of December to 15 h 06 min by month's end. Set against the rest of the year, December is Castro's 5th-clearest and 4th-windiest month. For the whole year in context, see Castro's year-round climate.

Daytime high
18°
4th warmest
Overnight low
10th coldest
Rainfall
82 mm
12.6 wet days
Daylight
15 h 06 min
6:18 AM – 9:24 PM
Cloud cover
70%
5th clearest
Wind
10 km/h
4th windiest
Solar energy
5.88 kWh/m²
Travel score
5.4
out of 10

Castro is Chilean city.

Density
2,926/km²
people per km²
Founded
1567

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 18°C through the month.

A typical December day in Castro reaches about 18°C in the afternoon and slips back to 9°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 14°C and 22°C. Set against its neighbours, December runs about 2°C warmer than November and about 2°C cooler than January.

10°15°20°25°151015202531
Avg high (°C)Avg low (°C)
1178
2178
3178
4178
5178
6178
7179
8189
9189
10189
11189
12189
13189
14189
15189
16189
17189
18189
19189
20189
21189
22189
23189
24189
25189
26189
27189
281810
291910
301910
311910

Castro weather by month

How December compares with the rest of the year at a glance. December is the 4th-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan20° / 10°639.814.86.2
Feb20° / 10°568.313.76.4
Mar18° / 8611.512.45.6
Apr15° / 11213.610.94.0
May12° / 17217.39.62.7
Jun10° / 19219.38.91.8
Jul10° / 17417.99.21.8
Aug11° / 19619.910.32.0
Sep12° / 13016.211.72.8
Oct14° / 12416.313.23.5
Nov16° / 9813.414.44.4
Dec18° / 8212.615.15.4

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 16% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 12% of December, with mostly cloudy or overcast conditions the remaining 72%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12872
22971
32872
42971
52971
63070
73070
83070
93070
102971
112971
122971
132872
142773
152773
162773
172575
182575
192674
202674
212674
222674
232773
242872
252872
262971
272971
282971
293070
303070
313070

Chance of precipitation in December

Any precipitation

Castro gets around 82 mm of rain over 12.6 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 40% and peaks near 42% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
140
240
339
439
539
639
739
839
939
1039
1139
1239
1340
1440
1540
1641
1741
1842
1942
2042
2142
2242
2341
2441
2541
2641
2740
2840
2939
3039
3139

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 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
7982
8973
9973
10973
11973
12973
13973
14973
15973
16973
17973
18973
19964
20964
21955
22955
23955
24946
25946
26946
27946
28937
29937
30937
31937

Wind in December

Winds average 10 km/h in December.

Across December, daily wind ranges from about 10 km/h on the calmest days to 11 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
110calm
210calm
310calm
410calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1710calm
1811calm
1911calm
2011calm
2111calm
2211calm
2311calm
2411calm
2511calm
2610calm
2710calm
2810calm
2910calm
3010calm
3110calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 14 h 54 min at the start of December to 15 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 12 minutes over December. Sunrise moves from 6:18 AM to 6:26 AM, and sunset from 9:11 PM to 9:30 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.96:189:11
214.96:189:12
314.96:189:13
414.96:189:14
515.06:189:15
615.06:179:16
715.06:179:17
815.06:179:18
915.06:179:19
1015.06:179:20
1115.16:179:21
1215.16:189:21
1315.16:189:22
1415.16:189:23
1515.16:189:24
1615.16:189:24
1715.16:199:25
1815.16:199:25
1915.16:199:26
2015.16:209:27
2115.16:209:27
2215.16:219:28
2315.16:219:28
2415.16:229:28
2515.16:229:29
2615.16:239:29
2715.16:239:30
2815.16:249:30
2915.16:259:30
3015.16:259:30
3115.16:269:30

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 5.88 kWh/m².

For context, solar energy here swings from a low near 1.16 kWh/m² to a high of 6.04 kWh/m² in January across the year — December's 5.88 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.7Bright
25.7Bright
35.8Bright
45.8Bright
55.8Bright
65.8Bright
75.8Bright
85.8Bright
95.9Bright
105.9Bright
115.9Bright
125.9Bright
135.9Bright
145.8Bright
155.8Bright
165.8Bright
175.8Bright
185.8Bright
195.8Bright
205.8Bright
215.8Bright
225.8Bright
235.8Bright
245.8Bright
255.8Bright
265.9Bright
275.9Bright
285.9Bright
295.9Bright
305.9Bright
316.0Bright
Planning a trip in December

Is December a good time to visit Castro?

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

5.4
Sightseeing
4th-best month of the year
1.7
Beach & pool
4th-best month of the year

December is a reasonable time to visit Castro for sightseeing.

What to pack for Castro in December

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

In December, Castro sees daytime highs around 18°C and nights near 9°C. Worth packing: rain gear and sun protection. About 13 days see rain.

rain gearsun protection

Sea temperature near Castro in December

The nearest coast averages about 13°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 31 km away) is warmest in January at about 14°C and coldest in August near 11°C.

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

10°12°14°16°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°C)Comfort
Jan14Bracing
Feb14Bracing
Mar14Bracing
Apr13Bracing
May12Bracing
Jun12Bracing
Jul11Bracing
Aug11Bracing
Sep11Bracing
Oct11Bracing
Nov12Bracing
Dec13Bracing

UV index in Castro in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Castro peaks around December 23 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 20 at about 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeModerateLowModerateHighVery highExtremeDec 23UV 12Jun 20UV 1
UV index (midday)Level
Jan11Extreme
Feb11Extreme
Mar7High
Apr4Moderate
May2Moderate
Jun1Low
Jul2Low
Aug2Moderate
Sep4Moderate
Oct7High
Nov8Very high
Dec12Extreme
Location & terrain

Where is Castro?

Castro sits at 42.5°S, 73.8°W, 81 m above sea level, in Chile. The nearest listed city is Ancud, 67 km away.

Topography around Castro

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

Within 3 km, the terrain around Castro has significant variations in elevation — a maximum elevation change of 306 m around an average of 69 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 835 m; within 80 km, large variations in elevation — a maximum elevation change of 847 m.

The land around Castro is covered by trees (39%), water (27%) and grassland (20%) within 3 km, trees (54%) and grassland (25%) within 16 km, and water (58%) and trees (34%) within 80 km.

3 km
306 m
16 km
835 m
80 km
847 m
treesgrasslandartificial surfaceswater
December weather nearby: Ancud 67 km · Quellón 73 km · Calbuco 94 km · Maullín 96 km · Puerto Montt 131 km · Puerto Varas 144 km · Llanquihue 149 km · Frutillar 161 km

Chile travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / F / L
220 V · 50 Hz
Prices
≈ 48% of US
price level, 2025
GDP per capita
$17,995
2025
Happiness
6.3 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
6.3
per 100k, 2023
Road deaths
14.9
per 100k/yr, 2019
Income group
High
World Bank
English
Moderate
EF EPI 517
Religion
Catholic 57%none 26%Evangelical or Protestant 16%other Christians and traditions related to Christ 1%

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 Castro (-42.4721°, -73.7732°, elevation 81 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).