Juan José Castelli weather in December

In December, Juan José Castelli sees average daytime highs of 33°C and overnight lows near 22°C, with 135 mm of rain across 11.1 wet days and about 13.6 hours of daylight. It is the 2nd-warmest and 4th-wettest month of the year here.

Highs climb over the month, from about 32°C in the first days to 34°C by the end. The sky is clear or mostly clear about 40% of the time in December, and the air most often feels oppressive.

Daylight stretches from about 13 h 30 min at the start of December to 13 h 36 min by month's end. Set against the rest of the year, December is Juan José Castelli's 8th-clearest and 6th-windiest month. For the whole year in context, see Juan José Castelli's year-round climate.

Daytime high
33°
2nd warmest
Overnight low
22°
10th coldest
Rainfall
135 mm
11.1 wet days
Daylight
13 h 36 min
6:10 AM – 7:47 PM
Cloud cover
53%
8th clearest
Wind
11 km/h
6th windiest
Solar energy
6.73 kWh/m²
Travel score
3.6
out of 10

Juan José Castelli is human settlement.

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

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 32°C in the first days to 34°C by the end.

A typical December day in Juan José Castelli reaches about 33°C in the afternoon and slips back to 22°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 28°C and 38°C. Set against its neighbours, December runs about 2°C warmer than November and about 1°C cooler than January.

15°20°25°30°35°40°151015202531
Avg high (°C)Avg low (°C)
13120
23220
33221
43221
53221
63221
73221
83221
93221
103221
113221
123221
133321
143321
153322
163322
173322
183322
193322
203322
213322
223322
233322
243322
253322
263322
273422
283422
293423
303423
313423

How December really feels in Juan José Castelli

Once humidity and wind are folded in, December averages 31 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
31
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in December is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Juan José Castelli weather by month

How December compares with the rest of the year at a glance. December is the 2nd-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan33° / 23°12411.213.43.3
Feb32° / 22°13711.112.93.8
Mar30° / 21°13711.112.24.8
Apr27° / 18°1179.311.46.5
May24° / 14°627.810.77.2
Jun22° / 13°436.810.47.1
Jul22° / 11°315.810.57.6
Aug25° / 13°404.511.18.1
Sep28° / 15°586.711.87.0
Oct30° / 18°1201012.65.2
Nov31° / 20°14010.113.34.6
Dec33° / 22°13511.113.63.6

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 40% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 17% of December, with mostly cloudy or overcast conditions the remaining 43%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15446
25446
35347
45446
55446
65446
75545
85545
95644
105743
115743
125941
135941
146040
156040
166139
176139
186139
196139
206040
215941
225941
235842
245743
255644
265545
275446
285446
295446
305446
315446

Chance of precipitation in December

Any precipitation

Juan José Castelli gets around 135 mm of rain over 11.1 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 36% and peaks near 38% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
137
237
337
436
536
635
735
835
934
1034
1134
1234
1333
1434
1534
1634
1734
1834
1935
2035
2136
2236
2337
2437
2538
2638
2738
2838
2937
3037
3136

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, December lands in the oppressive band about 35% of days. Sticky, muggy-or-worse air turns up on roughly 67% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
17112330281
27102230291
36102230301
46102230302
5692230312
6692230312
7692229312
8692229322
9692229322
10592229322
11592229332
125102229332
134102229332
144102129332
154102130332
164102030343
173102030343
183101930353
193101929353
203101829364
212101829374
222101728385
232101728395
24291628406
25191627406
26191527417
27191527417
28191526417
29191526418
30191526418
31191526418

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 30 min at the start of December to 13 h 36 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 6:07 AM to 6:18 AM, and sunset from 7:37 PM to 7:54 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.56:077:37
213.56:077:38
313.56:077:39
413.56:077:40
513.56:077:40
613.66:087:41
713.66:087:42
813.66:087:42
913.66:087:43
1013.66:087:43
1113.66:097:44
1213.66:097:45
1313.66:097:45
1413.66:107:46
1513.66:107:46
1613.66:107:47
1713.66:117:48
1813.66:117:48
1913.66:117:49
2013.66:127:49
2113.66:127:50
2213.66:137:50
2313.66:137:51
2413.66:147:51
2513.66:147:52
2613.66:157:52
2713.66:157:52
2813.66:167:53
2913.66:167:53
3013.66:177:53
3113.66:187:54

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 6.73 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 2.67 kWh/m² to a high of 6.73 kWh/m² in December across the year — December's 6.73 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
16.5Intense
26.5Intense
36.5Intense
46.5Intense
56.5Intense
66.5Intense
76.6Intense
86.6Intense
96.6Intense
106.7Intense
116.7Intense
126.7Intense
136.8Intense
146.8Intense
156.8Intense
166.8Intense
176.8Intense
186.8Intense
196.8Intense
206.9Intense
216.9Intense
226.9Intense
236.8Intense
246.8Intense
256.8Intense
266.8Intense
276.8Intense
286.8Intense
296.8Intense
306.8Intense
316.8Intense
Planning a trip in December

Is December a good time to visit Juan José Castelli?

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

3.6
Sightseeing
11th-best month of the year
6.2
Beach & pool
7th-best month of the year

December is a weaker month for outdoor sightseeing in Juan José Castelli. The water and warmth also suit a beach or pool day.

What to pack for Juan José Castelli in December

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

In December, Juan José Castelli sees daytime highs around 33°C and nights near 22°C. Pack light clothes and sun protection. Worth having: rain gear. About 11 days see rain.

light clothessun protectionrain gear

UV index in Juan José Castelli 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 Juan José Castelli peaks around January 18 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 11 at about 5 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highHighModerateHighVery highExtremeJan 18UV 14Jul 11UV 5
UV index (midday)Level
Jan15Extreme
Feb14Extreme
Mar12Extreme
Apr9Very high
May6High
Jun5Moderate
Jul5Moderate
Aug6High
Sep8Very high
Oct7High
Nov12Extreme
Dec14Extreme

Air quality in Juan José Castelli 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 Juan José Castelli is worst in August — around 31 µg/m³ PM2.5 (moderate), about 5.1× the cleanest month (April, 6 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodAug 2330 µg/m³Apr 236 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb10Good
Mar8Good
Apr6Good
May6Good
Jun7Good
Jul15Moderate
Aug31Moderate
Sep29Moderate
Oct18Moderate
Nov10Good
Dec9Good
Location & terrain

Where is Juan José Castelli?

Juan José Castelli sits at 25.9°S, 60.6°W, 113 m above sea level, in Argentina. The nearest listed city is Tres Isletas, 48 km away.

Topography around Juan José Castelli

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

Within 3 km, the terrain around Juan José Castelli has only modest variations in elevation — a maximum elevation change of 9 m around an average of 110 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 20 m; within 80 km, only modest variations in elevation — a maximum elevation change of 64 m.

The land around Juan José Castelli is covered by cropland (30%), artificial surfaces (29%) and grassland (22%) within 3 km, trees (56%) and cropland (30%) within 16 km, and trees (75%) within 80 km.

3 km
9 m
16 km
20 m
80 km
64 m
treesshrubsgrasslandcroplandartificial surfaces
December weather nearby: Tres Isletas 48 km · Presidencia Roque Sáenz Peña 96 km · Quitilipi 110 km · Machagai 123 km · Las Breñas 135 km · General José de San Martín 143 km · Charata 152 km · Pirané 153 km

Argentina travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / I
220 V · 50 Hz
Prices
≈ 46% of US
price level, 2025
GDP per capita
$14,898
2025
Happiness
6.4 / 10
World Happiness, 2025
Homicide rate
4.5
per 100k, 2023
Road deaths
14.1
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
High
EF EPI 575
Religion
Roman Catholic 63%none 19%Evangelical 15%Jehovah's Witness and Church of Jesus 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 Juan José Castelli (-25.9466°, -60.6201°, elevation 113 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).