San Bernardino weather in December

In December, San Bernardino sees average daytime highs of 32°C and overnight lows near 22°C, with 163 mm of rain across 12.7 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 32°C through the month. The sky is clear or mostly clear about 41% 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 San Bernardino's 10th-clearest and 8th-windiest month. For the whole year in context, see San Bernardino's year-round climate.

Daytime high
32°
3rd warmest
Overnight low
22°
10th coldest
Rainfall
163 mm
12.7 wet days
Daylight
13 h 36 min
5:58 AM – 7:32 PM
Cloud cover
53%
10th clearest
Wind
11 km/h
8th windiest
Solar energy
6.7 kWh/m²
Travel score
3.9
out of 10

San Bernardino is district of Paraguay.

Density
41/km²
people per km²
Founded
1881

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 32°C through the month.

A typical December day in San Bernardino reaches about 32°C in the afternoon and slips back to 22°C overnight — a 10°C spread between the day's warmth and the night's chill. On most days the high lands between 28°C and 35°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)
13121
23121
33121
43121
53121
63121
73121
83121
93121
103122
113222
123222
133222
143222
153222
163222
173222
183222
193222
203222
213222
223222
233222
243223
253223
263223
273223
283223
293223
303223
313323

How December really feels in San Bernardino

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.

San Bernardino 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
Jan33° / 23°12412.913.43.5
Feb32° / 23°14212.312.93.7
Mar31° / 22°10910.312.24.6
Apr28° / 19°1428.911.46.2
May24° / 16°1308.810.87.2
Jun23° / 14°978.310.57.1
Jul23° / 13°827.710.67.4
Aug26° / 15°706.611.17.7
Sep27° / 16°1138.611.86.9
Oct29° / 19°19612.112.65.3
Nov30° / 20°17711.113.24.8
Dec32° / 22°16312.713.53.9

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 41% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 15% of December, with mostly cloudy or overcast conditions the remaining 44%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15446
25446
35347
45446
55446
65347
75347
85446
95446
105644
115644
125644
135644
145743
155743
165842
175842
185842
195842
205941
215842
225842
235842
245743
255743
265743
275743
285743
295743
305743
315743

Chance of precipitation in December

Any precipitation

San Bernardino gets around 163 mm of rain over 12.7 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 45% on the wettest days.

0%20%40%60%151015202531
Rain chance (%)
139
240
340
440
540
640
739
839
938
1038
1138
1237
1337
1437
1537
1637
1738
1838
1938
2039
2140
2241
2342
2443
2544
2644
2745
2845
2945
3044
3144

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 50% of days. Sticky, muggy-or-worse air turns up on roughly 81% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1381633391
2371632401
3371632411
4371531421
5371531431
6371531441
7271530451
8271530451
9271430461
10261429471
11261429471
12261429481
13261429491
14251329501
15251329501
16251328502
17241228522
18241228522
19141128533
20141127543
21141127534
22131026555
23131025565
2413925566
2513924567
2603924568
2703923578
2803922579
29039225610
30039215710
31039215611

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 12 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
112calm
212calm
312calm
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 5:55 AM to 6:06 AM, and sunset from 7:23 PM to 7:39 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.55:557:23
213.55:557:24
313.55:557:24
413.55:557:25
513.55:557:26
613.55:567:26
713.55:567:27
813.55:567:28
913.55:567:28
1013.55:567:29
1113.55:577:29
1213.65:577:30
1313.65:577:31
1413.65:587:31
1513.65:587:32
1613.65:587:32
1713.65:597:33
1813.65:597:33
1913.65:597:34
2013.66:007:35
2113.66:007:35
2213.66:017:35
2313.66:017:36
2413.66:027:36
2513.66:027:37
2613.66:037:37
2713.66:037:38
2813.66:047:38
2913.66:047:38
3013.66:057:39
3113.66:067:39

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 6.7 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 2.8 kWh/m² to a high of 6.7 kWh/m² in December across the year — December's 6.7 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
16.5Intense
26.5Intense
36.5Intense
46.6Intense
56.6Intense
66.6Intense
76.6Intense
86.6Intense
96.7Intense
106.7Intense
116.7Intense
126.7Intense
136.7Intense
146.8Intense
156.8Intense
166.8Intense
176.8Intense
186.8Intense
196.8Intense
206.8Intense
216.8Intense
226.8Intense
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 San Bernardino?

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

3.9
Sightseeing
10th-best month of the year
6.2
Beach & pool
7th-best month of the year

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

What to pack for San Bernardino in December

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

In December, San Bernardino sees daytime highs around 32°C and nights near 22°C. Pack light clothes and sun protection. Worth having: rain gear. About 13 days see rain.

light clothessun protectionrain gear

UV index in San Bernardino in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 13 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in San Bernardino peaks around January 17 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 15 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 17UV 15Jul 15UV 5
UV index (midday)Level
Jan15Extreme
Feb14Extreme
Mar11Extreme
Apr9Very high
May6High
Jun5Moderate
Jul5Moderate
Aug5High
Sep8Very high
Oct8Very high
Nov12Extreme
Dec13Extreme

Air quality in San Bernardino 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 San Bernardino is worst in September — around 28 µg/m³ PM2.5 (moderate), about 2.9× the cleanest month (December, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodGoodModerateGoodSep 1227 µg/m³Dec 1910 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb12Moderate
Mar11Good
Apr13Moderate
May13Moderate
Jun15Moderate
Jul17Moderate
Aug25Moderate
Sep28Moderate
Oct18Moderate
Nov13Moderate
Dec10Good
Location & terrain

Where is San Bernardino?

San Bernardino sits at 25.3°S, 57.3°W, 0 m above sea level, in Paraguay. The nearest listed city is Areguá, 9.0 km away.

Topography around San Bernardino

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

Within 3 km, the terrain around San Bernardino has only modest variations in elevation — a maximum elevation change of 183 m around an average of 91 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 272 m; within 80 km, significant variations in elevation — a maximum elevation change of 529 m.

The land around San Bernardino is covered by trees (51%) and water (42%) within 3 km, trees (72%) within 16 km, and grassland (52%) and trees (39%) within 80 km.

3 km
183 m
16 km
272 m
80 km
529 m
treesgrasslandcroplandartificial surfaceswaterwetland
December weather nearby: Areguá 9.0 km · Itauguá 11 km · Capiatá 16 km · Caacupé 18 km · San Lorenzo 22 km · Itá 22 km · Fernando de la Mora 23 km · Limpio 25 km

Paraguay travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type A / B / C / N
220 V · 50 Hz
Prices
≈ 35% of US
price level, 2025
GDP per capita
$7,027
2025
Happiness
6.2 / 10
World Happiness, 2025
Safe drinking water
64%
of population, 2024
Homicide rate
6.8
per 100k, 2023
Road deaths
22
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Moderate
EF EPI 531
Religion
Roman Catholic 80%Protestant 7%Believer 6%other 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 San Bernardino (-25.3107°, -57.2963°, elevation 0 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).