Castro weather in December

In December, Castro sees average daytime highs of 26°C and overnight lows near 17°C, with 173 mm of rain across 20.3 wet days and about 13.5 hours of daylight. It is the 3rd-warmest and 3rd-wettest month of the year here.

Day-to-day highs hold fairly steady near 26°C through the month. The sky is clear or mostly clear about 13% of the time in December, and the air most often feels humid.

Daylight stretches from about 13 h 24 min at the start of December to 13 h 30 min by month's end. Set against the rest of the year, December is Castro's 10th-clearest and 5th-windiest month. For the whole year in context, see Castro's year-round climate.

Daytime high
26°
3rd warmest
Overnight low
17°
10th coldest
Rainfall
173 mm
20.3 wet days
Daylight
13 h 30 min
6:30 AM – 8:02 PM
Cloud cover
71%
10th clearest
Wind
11 km/h
5th windiest
Solar energy
5.87 kWh/m²
Travel score
5.1
out of 10

Castro is human settlement in Brazil.

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 26°C through the month.

A typical December day in Castro reaches about 26°C in the afternoon and slips back to 17°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 22°C and 29°C. Set against its neighbours, December runs about 1°C warmer than November and on par with January.

10°15°20°25°30°151015202531
Avg high (°C)Avg low (°C)
12516
22516
32516
42516
52516
62516
72516
82516
92516
102516
112516
122516
132516
142516
152516
162617
172617
182617
192617
202617
212617
222617
232617
242617
252617
262617
272617
282617
292617
302617
312617

Castro weather by month

How December compares with the rest of the year at a glance. December is the 3rd-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan26° / 17°23523.813.44.5
Feb26° / 17°1782112.94.6
Mar25° / 17°1321812.25.5
Apr23° / 15°709.611.46.9
May20° / 12°898.910.86.5
Jun19° / 11°938.410.56.5
Jul19° / 10°79710.66.8
Aug21° / 11°727.311.17.2
Sep22° / 12°12710.411.86.6
Oct23° / 14°13815.112.65.9
Nov24° / 15°13316.113.25.8
Dec26° / 17°17320.313.55.1

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 13% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 20% of December, with mostly cloudy or overcast conditions the remaining 66%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13565
23664
33466
43565
53466
63565
73466
83466
93466
103565
113565
123565
133565
143565
153565
163565
173565
183565
193565
203565
213565
223466
233367
243367
253169
263169
273070
283070
293070
302872
312872

Chance of precipitation in December

Any precipitation

Castro gets around 173 mm of rain over 20.3 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 65% and peaks near 73% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
157
258
359
460
560
661
761
862
962
1063
1163
1264
1364
1465
1565
1665
1766
1866
1967
2067
2168
2268
2369
2469
2570
2670
2771
2872
2972
3073
3173

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, December lands in the humid band about 45% of days. Sticky, muggy-or-worse air turns up on roughly 28% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)
110284616
29284716
38274717
48274718
57264818
67264819
77264820
87254820
96254821
106244822
116244822
126244723
136234724
146234724
156234625
166224626
176224527
185224528
195224429
205214330
215214331
224214233
234204234
243204235
253194136
263194138
272184039
282184040
292184041
302174042
311173942

Wind in December

Winds average 11 km/h in December.

Across December, daily wind ranges from about 11 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
111calm
211calm
311calm
411calm
511calm
611calm
711calm
811calm
911calm
1011calm
1111calm
1211calm
1311calm
1411calm
1511calm
1611calm
1711calm
1811calm
1911calm
2011calm
2111calm
2211calm
2311calm
2411calm
2511calm
2611calm
2711calm
2811calm
2911calm
3011calm
3111calm

Sunrise & sunset in December

DaylightNight

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

Days grow by about 6 minutes over December. Sunrise moves from 6:27 AM to 6:38 AM, and sunset from 7:53 PM to 8:09 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.46:277:53
213.46:277:53
313.46:277:54
413.56:277:55
513.56:277:55
613.56:287:56
713.56:287:57
813.56:287:57
913.56:287:58
1013.56:287:59
1113.56:297:59
1213.56:298:00
1313.56:298:00
1413.56:308:01
1513.56:308:02
1613.56:308:02
1713.56:318:03
1813.56:318:03
1913.56:318:04
2013.56:328:04
2113.56:328:05
2213.56:338:05
2313.56:338:06
2413.56:348:06
2513.56:348:07
2613.56:358:07
2713.56:358:07
2813.56:368:08
2913.56:368:08
3013.56:378:08
3113.56:388:09

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 5.87 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 3.05 kWh/m² to a high of 5.87 kWh/m² in December across the year — December's 5.87 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.9Bright
25.9Bright
35.8Bright
45.8Bright
55.8Bright
65.8Bright
75.8Bright
85.8Bright
95.8Bright
105.8Bright
115.8Bright
125.9Bright
135.9Bright
145.9Bright
155.9Bright
165.9Bright
175.9Bright
185.9Bright
195.9Bright
205.9Bright
215.9Bright
225.9Bright
235.9Bright
245.9Bright
255.9Bright
265.8Bright
275.8Bright
285.8Bright
295.8Bright
305.8Bright
315.8Bright
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).

5.1
Sightseeing
10th-best month of the year
4.7
Beach & pool
6th-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 26°C and nights near 17°C. Pack rain gear. Worth having: light clothes and sun protection. About 20 days see rain.

rain gearlight clothessun protection

UV index in Castro in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 14 (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 January 19 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 13 at about 5 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highHighExtremeJan 19UV 15Jul 13UV 5
UV index (midday)Level
Jan15Extreme
Feb15Extreme
Mar12Extreme
Apr9Very high
May7High
Jun6High
Jul5High
Aug7High
Sep5High
Oct11Extreme
Nov14Extreme
Dec14Extreme

Air quality in Castro 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 Castro is worst in September — around 17 µg/m³ PM2.5 (moderate), about 2.6× the cleanest month (March, 6 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodSep 1316 µg/m³Mar 136 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb7Good
Mar6Good
Apr7Good
May8Good
Jun8Good
Jul10Good
Aug14Moderate
Sep17Moderate
Oct10Good
Nov7Good
Dec7Good
Location & terrain

Where is Castro?

Castro sits at 24.8°S, 50.0°W, 986 m above sea level, in Brazil. The nearest listed city is Piraí do Sul, 30 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 only modest variations in elevation — a maximum elevation change of 151 m around an average of 1,004 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 304 m; within 80 km, large variations in elevation — a maximum elevation change of 1,128 m.

The land around Castro is covered by trees (42%), artificial surfaces (28%) and grassland (20%) within 3 km, trees (42%) and cropland (42%) within 16 km, and trees (58%) and cropland (30%) within 80 km.

3 km
151 m
16 km
304 m
80 km
1,128 m
treesgrasslandcroplandartificial surfaceswater
December weather nearby: Piraí do Sul 30 km · Ponta Grossa 37 km · Tibagi 51 km · Jaguariaíva 68 km · Palmeira 71 km · Arapoti 73 km · Cerro Azul 76 km · Imbituva 77 km

Brazil travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / N
127 / 220 V · 60 Hz
Prices
≈ 46% of US
price level, 2025
GDP per capita
$10,713
2025
Happiness
6.6 / 10
World Happiness, 2025
Safe drinking water
89%
of population, 2024
Homicide rate
19.3
per 100k, 2023
Road deaths
16
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 482
Religion
Roman Catholic 57%Evangelical 27%none 9%other 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 Castro (-24.7893°, -50.0123°, elevation 986 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).