La Unión weather in December

In December, La Unión sees average daytime highs of 28°C and overnight lows near 16°C, with 86 mm of rain across 8.6 wet days and about 14.3 hours of daylight. It is the 3rd-warmest and 6th-wettest month of the year here.

Highs climb over the month, from about 26°C in the first days to 29°C by the end. The sky is clear or mostly clear about 50% of the time in December, and the air most often feels dry.

Daylight stretches from about 14 h 12 min at the start of December to 14 h 18 min by month's end. Set against the rest of the year, December is La Unión's 2nd-clearest and 5th-windiest month. For the whole year in context, see La Unión's year-round climate.

Daytime high
28°
3rd warmest
Overnight low
16°
10th coldest
Rainfall
86 mm
8.6 wet days
Daylight
14 h 18 min
5:40 AM – 8:00 PM
Cloud cover
43%
2nd clearest
Wind
13 km/h
5th windiest
Solar energy
7.48 kWh/m²
Travel score
6.7
out of 10

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 26°C in the first days to 29°C by the end.

A typical December day in La Unión reaches about 28°C in the afternoon and slips back to 16°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 23°C and 32°C. Set against its neighbours, December runs about 3°C warmer than November and about 1°C cooler than January.

10°20°30°151015202531
Avg high (°C)Avg low (°C)
12615
22615
32615
42715
52715
62715
72715
82715
92716
102716
112716
122716
132716
142816
152816
162816
172816
182817
192817
202817
212817
222817
232817
242817
252817
262917
272918
282918
292918
302918
312918

La Unión weather by month

How December compares with the rest of the year at a glance. December is the 3rd-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan29° / 18°897.914.16.0
Feb28° / 17°898.613.36.6
Mar26° / 16°817.212.37.4
Apr22° / 12°908.211.17.1
May18° / 596.110.26.4
Jun15° / 605.69.75.1
Jul14° / 596.19.94.6
Aug16° / 64610.75.8
Sep18° / 72711.86.4
Oct21° / 11°1069.412.96.7
Nov24° / 14°948.413.87.2
Dec28° / 16°868.614.36.7

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 50% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 14% of December, with mostly cloudy or overcast conditions the remaining 36%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16337
26337
36436
46436
56436
66535
76535
86535
96535
106535
116535
126436
136436
146436
156436
166337
176436
186436
196436
206436
216436
226436
236436
246436
256436
266436
276436
286436
296436
306535
316535

Chance of precipitation in December

Any precipitation

La Unión gets around 86 mm of rain over 8.6 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 28% and peaks near 29% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
125
225
326
426
526
627
727
827
927
1027
1128
1228
1328
1429
1529
1629
1729
1829
1929
2028
2128
2228
2329
2429
2529
2629
2729
2829
2929
3029
3129

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 30% of days. Sticky, muggy-or-worse air turns up on roughly 16% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
142272560
242262570
342262570
442262570
542252580
641252580
740252680
840262681
939262691
1038262691
1137272791
1235272791
13342728101
14332728101
15322729111
16312729121
17292729131
18282730142
19272630152
20262630162
21242530182
22232530192
23232430213
24222330223
25212230233
26202131243
27202130254
28192030264
29182030274
30182030284
31171930285

Wind in December

Winds average 13 km/h in December.

Across December, daily wind ranges from about 13 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
114light breeze
214light breeze
314light breeze
414light breeze
514light breeze
614light breeze
714light breeze
814light breeze
914light breeze
1013light breeze
1113light breeze
1213light breeze
1313light breeze
1413light breeze
1513light breeze
1613light breeze
1713light breeze
1813light breeze
1913light breeze
2013light breeze
2113light breeze
2213light breeze
2313light breeze
2413light breeze
2513light breeze
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze
3113light breeze

Sunrise & sunset in December

DaylightNight

Daylight runs from about 14 h 12 min at the start of December to 14 h 18 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 5:39 AM to 5:48 AM, and sunset from 7:49 PM to 8:07 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.25:397:49
214.25:397:50
314.25:397:51
414.25:397:52
514.25:397:52
614.25:397:53
714.35:397:54
814.35:397:55
914.35:397:56
1014.35:397:56
1114.35:397:57
1214.35:397:58
1314.35:407:58
1414.35:407:59
1514.35:408:00
1614.35:408:00
1714.35:418:01
1814.35:418:01
1914.35:418:02
2014.35:428:03
2114.35:428:03
2214.35:438:03
2314.35:438:04
2414.35:448:04
2514.35:448:05
2614.35:458:05
2714.35:458:06
2814.35:468:06
2914.35:478:06
3014.35:478:06
3114.35:488:07

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 7.48 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 2.23 kWh/m² to a high of 7.48 kWh/m² in December across the year — December's 7.48 kWh/m² sits near the top of that range.

02468151015202531
Solar energy (kWh/m²)Level
17.3Intense
27.4Intense
37.4Intense
47.4Intense
57.4Intense
67.4Intense
77.5Intense
87.5Intense
97.5Intense
107.5Intense
117.5Intense
127.5Intense
137.5Intense
147.5Intense
157.5Intense
167.5Intense
177.5Intense
187.5Intense
197.5Intense
207.5Intense
217.5Intense
227.5Intense
237.4Intense
247.4Intense
257.4Intense
267.4Intense
277.4Intense
287.4Intense
297.4Intense
307.4Intense
317.4Intense
Planning a trip in December

Is December a good time to visit La Unión?

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

6.7
Sightseeing
4th-best month of the year
7.2
Beach & pool
2nd-best month of the year

December is a reasonable time to visit La Unión for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for La Unión in December

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

In December, La Unión sees daytime highs around 28°C and nights near 16°C. Pack light clothes and sun protection. Worth having: rain gear. About 9 days see rain.

light clothessun protectionrain gear

Sea temperature near La Unión in December

The nearest coast averages about 23°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 32 km away) is warmest in January at about 25°C and coldest in July near 13°C.

It's comfortable for a long swim from Nov 9 to Apr 20 — about 5.4 months when the water holds above 20°C.

10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swimcomfortable to swim
Sea temperature (°C)Comfort
Jan25Warm
Feb25Warm
Mar23Refreshing
Apr21Refreshing
May17Cool
Jun14Bracing
Jul13Bracing
Aug13Bracing
Sep15Cool
Oct18Cool
Nov21Refreshing
Dec23Refreshing

UV index in La Unión 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 La Unión peaks around January 14 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 19 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highModerateHighVery highExtremeJan 14UV 12Jun 19UV 3
UV index (midday)Level
Jan13Extreme
Feb11Extreme
Mar10Very high
Apr6High
May3Moderate
Jun3Moderate
Jul3Moderate
Aug4Moderate
Sep6High
Oct8Very high
Nov11Extreme
Dec12Extreme

Air quality in La Unión 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 La Unión is worst in August — around 17 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (December, 9 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodAug 1316 µg/m³Dec 129 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb10Good
Mar11Good
Apr12Good
May14Moderate
Jun15Moderate
Jul16Moderate
Aug17Moderate
Sep14Moderate
Oct11Good
Nov10Good
Dec9Good
Location & terrain

Where is La Unión?

La Unión sits at 34.9°S, 58.5°W, 18 m above sea level, in Argentina. The nearest listed city is Tristán Suárez, 3.0 km away.

Topography around La Unión

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

Within 3 km, the terrain around La Unión has only modest variations in elevation — a maximum elevation change of 23 m around an average of 21 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 53 m; within 80 km, only modest variations in elevation — a maximum elevation change of 72 m.

The land around La Unión is covered by artificial surfaces (43%), trees (26%) and grassland (26%) within 3 km, grassland (41%) and artificial surfaces (27%) within 16 km, and grassland (35%) and cropland (28%) within 80 km.

3 km
23 m
16 km
53 m
80 km
72 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
December weather nearby: Tristán Suárez 3.0 km · Ezeiza 3.0 km · Burzaco 15 km · Adrogué 17 km · Lomas de Zamora 18 km · San Vicente 20 km · Banfield 20 km · Isidro Casanova 20 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 La Unión (-34.8756°, -58.5419°, elevation 18 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. 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).