San Juan weather in December

In December, San Juan sees average daytime highs of 30°C and overnight lows near 24°C, with 263 mm of rain across 27.2 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 30°C through the month. The sky is clear or mostly clear about 2% of the time in December, and the air most often feels miserable.

Daylight stretches from about 12 h 12 min at the start of December to 12 h 12 min by month's end. Set against the rest of the year, December is San Juan's 9th-clearest and 2nd-windiest month. For the whole year in context, see San Juan's year-round climate.

Daytime high: 30°; 4th warmest
Overnight low: 24°; 9th coldest
Rainfall: 263 mm; 27.2 wet days
Daylight: 12 h 12 min; 5:43 AM – 5:56 PM
Cloud cover: 85%; 9th clearest
Wind: 4 km/h; 2nd windiest
Solar energy: 4.6 kWh/m²
Travel score: 2.9; out of 10

San Juan is human settlement.

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

← November San Juan year-round climate January →Best places to visit in December

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 30°C through the month.

A typical December day in San Juan reaches about 30°C in the afternoon and slips back to 24°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 28°C and 32°C. Set against its neighbours, December runs on par with November and on par with January.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Avg high (°C)	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30
Avg low (°C)	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24	24

	Avg high (°C)	Avg low (°C)
1	30	24
2	30	24
3	30	24
4	30	24
5	30	24
6	30	24
7	30	24
8	30	24
9	30	24
10	30	24
11	30	24
12	30	24
13	30	24
14	30	24
15	30	24
16	30	24
17	30	24
18	30	24
19	30	24
20	30	24
21	30	24
22	30	24
23	30	24
24	30	24
25	30	24
26	30	24
27	30	24
28	30	24
29	30	24
30	30	24
31	30	24

How December really feels in San Juan

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

heat index over the day's high

Days feeling ≤ 0°C

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 Juan weather by month

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

Month	High / Low (°C)	Rainfall (mm)	Wet days	Daylight (hours)	Travel score
Jan	30° / 24°	252	25.9	12.2	3.0
Feb	30° / 24°	233	24.5	12.1	2.9
Mar	30° / 24°	304	28.4	12	2.8
Apr	30° / 23°	294	27.3	11.9	2.9
May	29° / 23°	271	26.7	11.8	3.2
Jun	29° / 23°	219	25	11.8	3.4
Jul	29° / 22°	166	23.3	11.8	3.8
Aug	30° / 22°	154	21.8	11.9	3.6
Sep	31° / 23°	179	23.5	12	3.2
Oct	31° / 23°	201	25.9	12.1	2.9
Nov	30° / 24°	235	25.8	12.2	2.9
Dec	30° / 24°	263	27.2	12.2	2.9

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 2% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 6% of December, with mostly cloudy or overcast conditions the remaining 92%.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Clearer (%)	11	11	11	11	10	10	10	9	8	8	8	8	8	7	7	7	7	7	7	7	8	7	7	7	7	8	8	8	8	9	10
Cloudier (%)	89	89	89	89	90	90	90	91	92	92	92	92	92	93	93	93	93	93	93	93	92	93	93	93	93	92	92	92	92	91	90

	Clearer (%)	Cloudier (%)
1	11	89
2	11	89
3	11	89
4	11	89
5	10	90
6	10	90
7	10	90
8	9	91
9	8	92
10	8	92
11	8	92
12	8	92
13	8	92
14	7	93
15	7	93
16	7	93
17	7	93
18	7	93
19	7	93
20	7	93
21	8	92
22	7	93
23	7	93
24	7	93
25	7	93
26	8	92
27	8	92
28	8	92
29	8	92
30	9	91
31	10	90

Chance of precipitation in December

Any precipitation

San Juan gets around 263 mm of rain over 27.2 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 88% and peaks near 90% on the wettest days.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Rain chance (%)	87	88	88	88	88	89	89	89	89	89	89	89	89	90	89	89	89	89	89	88	88	87	87	87	86	86	86	85	85	85	85

	Rain chance (%)
1	87
2	88
3	88
4	88
5	88
6	89
7	89
8	89
9	89
10	89
11	89
12	89
13	89
14	90
15	89
16	89
17	89
18	89
19	89
20	88
21	88
22	87
23	87
24	87
25	86
26	86
27	86
28	85
29	85
30	85
31	85

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, December lands in the miserable band about 54% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Oppressive (%)	34	34	35	36	36	37	38	39	40	41	42	43	45	46	47	48	49	50	51	52	52	53	53	54	54	54	54	54	54	54	54
Miserable (%)	66	66	65	64	64	63	62	61	60	59	58	57	55	54	53	52	51	50	49	48	48	47	47	46	46	46	46	46	46	46	46

	Oppressive (%)	Miserable (%)
1	34	66
2	34	66
3	35	65
4	36	64
5	36	64
6	37	63
7	38	62
8	39	61
9	40	60
10	41	59
11	42	58
12	43	57
13	45	55
14	46	54
15	47	53
16	48	52
17	49	51
18	50	50
19	51	49
20	52	48
21	52	48
22	53	47
23	53	47
24	54	46
25	54	46
26	54	46
27	54	46
28	54	46
29	54	46
30	54	46
31	54	46

Wind in December

Winds average 4 km/h in December.

Across December, daily wind ranges from about 4 km/h on the calmest days to 5 km/h at its breeziest. It stays fairly steady from day to day.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Wind speed (km/h)	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	5	5	5	5	5	5	5
Feels	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm

	Wind speed (km/h)	Feels
1	4	calm
2	4	calm
3	4	calm
4	4	calm
5	4	calm
6	4	calm
7	4	calm
8	4	calm
9	4	calm
10	4	calm
11	4	calm
12	4	calm
13	4	calm
14	4	calm
15	4	calm
16	4	calm
17	4	calm
18	4	calm
19	4	calm
20	4	calm
21	4	calm
22	4	calm
23	4	calm
24	4	calm
25	5	calm
26	5	calm
27	5	calm
28	5	calm
29	5	calm
30	5	calm
31	5	calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 12 h 12 min at the start of December to 12 h 12 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 0 minutes over December. Sunrise moves from 5:37 AM to 5:50 AM, and sunset from 5:49 PM to 6:03 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Daylight (h)	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2	12.2
Sunrise (AM)	5:37	5:37	5:37	5:38	5:38	5:39	5:39	5:39	5:40	5:40	5:41	5:41	5:41	5:42	5:42	5:43	5:43	5:44	5:44	5:45	5:45	5:46	5:46	5:46	5:47	5:47	5:48	5:48	5:49	5:49	5:50
Sunset (PM)	5:49	5:49	5:50	5:50	5:51	5:51	5:52	5:52	5:53	5:53	5:53	5:54	5:54	5:55	5:55	5:56	5:56	5:57	5:57	5:58	5:58	5:59	5:59	6:00	6:00	6:01	6:01	6:01	6:02	6:02	6:03

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	12.2	5:37	5:49
2	12.2	5:37	5:49
3	12.2	5:37	5:50
4	12.2	5:38	5:50
5	12.2	5:38	5:51
6	12.2	5:39	5:51
7	12.2	5:39	5:52
8	12.2	5:39	5:52
9	12.2	5:40	5:53
10	12.2	5:40	5:53
11	12.2	5:41	5:53
12	12.2	5:41	5:54
13	12.2	5:41	5:54
14	12.2	5:42	5:55
15	12.2	5:42	5:55
16	12.2	5:43	5:56
17	12.2	5:43	5:56
18	12.2	5:44	5:57
19	12.2	5:44	5:57
20	12.2	5:45	5:58
21	12.2	5:45	5:58
22	12.2	5:46	5:59
23	12.2	5:46	5:59
24	12.2	5:46	6:00
25	12.2	5:47	6:00
26	12.2	5:47	6:01
27	12.2	5:48	6:01
28	12.2	5:48	6:01
29	12.2	5:49	6:02
30	12.2	5:49	6:02
31	12.2	5:50	6:03

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 4.6 kWh/m².

For context, solar energy here swings from a low near 3.76 kWh/m² to a high of 5.14 kWh/m² in September across the year — December's 4.6 kWh/m² falls in the middle.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Solar energy (kWh/m²)	4.7	4.7	4.7	4.7	4.7	4.7	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6
Level	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright

	Solar energy (kWh/m²)	Level
1	4.7	Bright
2	4.7	Bright
3	4.7	Bright
4	4.7	Bright
5	4.7	Bright
6	4.7	Bright
7	4.6	Bright
8	4.6	Bright
9	4.6	Bright
10	4.6	Bright
11	4.6	Bright
12	4.6	Bright
13	4.6	Bright
14	4.6	Bright
15	4.6	Bright
16	4.6	Bright
17	4.6	Bright
18	4.6	Bright
19	4.6	Bright
20	4.6	Bright
21	4.6	Bright
22	4.6	Bright
23	4.6	Bright
24	4.6	Bright
25	4.6	Bright
26	4.6	Bright
27	4.6	Bright
28	4.6	Bright
29	4.6	Bright
30	4.6	Bright
31	4.6	Bright

Planning a trip in December

Is December a good time to visit San Juan?

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

2.9

Sightseeing

7th-best month of the year

4.0

Beach & pool

10th-best month of the year

December is a weaker month for outdoor sightseeing in San Juan.

What to pack for San Juan in December

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

In December, San Juan sees daytime highs around 30°C and nights near 24°C. Pack light clothes and rain gear. Worth having: sun protection. About 27 days see rain.

light clothesrain gearsun protection

UV index in San Juan 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 San Juan peaks around February 13 at about 16 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near August 14 at about 9 (very high).

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

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	15	16	15	12	13	11	10	9	12	12	12	12
Level	Extreme	Extreme	Extreme	Extreme	Extreme	Extreme	Extreme	Very high	Extreme	Extreme	Extreme	Extreme

	UV index (midday)	Level
Jan	15	Extreme
Feb	16	Extreme
Mar	15	Extreme
Apr	12	Extreme
May	13	Extreme
Jun	11	Extreme
Jul	10	Extreme
Aug	9	Very high
Sep	12	Extreme
Oct	12	Extreme
Nov	12	Extreme
Dec	12	Extreme

Air quality in San Juan 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 Juan is worst in March — around 15 µg/m³ PM2.5 (moderate), about 1.7× the cleanest month (June, 9 µg/m³).

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

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
PM2.5 (µg/m³)	14	15	15	12	10	9	10	13	15	10	11	12
Level	Moderate	Moderate	Moderate	Moderate	Good	Good	Good	Moderate	Moderate	Good	Good	Moderate

	PM2.5 (µg/m³)	Level
Jan	14	Moderate
Feb	15	Moderate
Mar	15	Moderate
Apr	12	Moderate
May	10	Good
Jun	9	Good
Jul	10	Good
Aug	13	Moderate
Sep	15	Moderate
Oct	10	Good
Nov	11	Good
Dec	12	Moderate

Location & terrain

Where is San Juan?

San Juan sits at 3.8°S, 73.3°W, 99 m above sea level, in Peru. The nearest listed city is Belen, 4.0 km away.

Topography around San Juan

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

Within 3 km, the terrain around San Juan has only modest variations in elevation — a maximum elevation change of 37 m around an average of 94 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 78 m; within 80 km, only modest variations in elevation — a maximum elevation change of 116 m.

The land around San Juan is covered by trees (53%) and artificial surfaces (30%) within 3 km, trees (79%) within 16 km, and trees (96%) within 80 km.

3 km

37 m

trees 53%

16 km

78 m

trees 79%

80 km

116 m

trees 96%

treesgrasslandartificial surfaceswater

← November San Juan year-round climate January →Best places to visit in December

December weather nearby: Belen 4.0 km · Iquitos 4.0 km · Requena 156 km · Atalaia do Norte 349 km · Benjamin Constant 367 km · Leticia 374 km · Tabatinga 374 km · Yurimaguas 394 km

Peru travel facts

Travel advisory: Level 2; Exercise Increased Caution
Power plugs: Type A / B / C; 220 V · 60 Hz
Prices: ≈ 51% of US; price level, 2025
GDP per capita: $9,684; 2025
Happiness: 6.0 / 10; World Happiness, 2025
Safe drinking water: 49%; of population, 2024
Homicide rate: 8.6; per 100k, 2021
Road deaths: 13.6; per 100k/yr, 2019
Income group: Upper middle; World Bank
English: Moderate; EF EPI 519
Religion

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 Juan (-3.7761°, -73.2814°, elevation 99 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).

	Avg high (°C)	Avg low (°C)
1	30	24
2	30	24
3	30	24
4	30	24
5	30	24
6	30	24
7	30	24
8	30	24
9	30	24
10	30	24
11	30	24
12	30	24
13	30	24
14	30	24
15	30	24
16	30	24
17	30	24
18	30	24
19	30	24
20	30	24
21	30	24
22	30	24
23	30	24
24	30	24
25	30	24
26	30	24
27	30	24
28	30	24
29	30	24
30	30	24
31	30	24

	Clearer (%)	Cloudier (%)
1	11	89
2	11	89
3	11	89
4	11	89
5	10	90
6	10	90
7	10	90
8	9	91
9	8	92
10	8	92
11	8	92
12	8	92
13	8	92
14	7	93
15	7	93
16	7	93
17	7	93
18	7	93
19	7	93
20	7	93
21	8	92
22	7	93
23	7	93
24	7	93
25	7	93
26	8	92
27	8	92
28	8	92
29	8	92
30	9	91
31	10	90

	Rain chance (%)
1	87
2	88
3	88
4	88
5	88
6	89
7	89
8	89
9	89
10	89
11	89
12	89
13	89
14	90
15	89
16	89
17	89
18	89
19	89
20	88
21	88
22	87
23	87
24	87
25	86
26	86
27	86
28	85
29	85
30	85
31	85

	Oppressive (%)	Miserable (%)
1	34	66
2	34	66
3	35	65
4	36	64
5	36	64
6	37	63
7	38	62
8	39	61
9	40	60
10	41	59
11	42	58
12	43	57
13	45	55
14	46	54
15	47	53
16	48	52
17	49	51
18	50	50
19	51	49
20	52	48
21	52	48
22	53	47
23	53	47
24	54	46
25	54	46
26	54	46
27	54	46
28	54	46
29	54	46
30	54	46
31	54	46

	Avg high (°C)	Avg low (°C)
1	30	24
2	30	24
3	30	24
4	30	24
5	30	24
6	30	24
7	30	24
8	30	24
9	30	24
10	30	24
11	30	24
12	30	24
13	30	24
14	30	24
15	30	24
16	30	24
17	30	24
18	30	24
19	30	24
20	30	24
21	30	24
22	30	24
23	30	24
24	30	24
25	30	24
26	30	24
27	30	24
28	30	24
29	30	24
30	30	24
31	30	24

	Clearer (%)	Cloudier (%)
1	11	89
2	11	89
3	11	89
4	11	89
5	10	90
6	10	90
7	10	90
8	9	91
9	8	92
10	8	92
11	8	92
12	8	92
13	8	92
14	7	93
15	7	93
16	7	93
17	7	93
18	7	93
19	7	93
20	7	93
21	8	92
22	7	93
23	7	93
24	7	93
25	7	93
26	8	92
27	8	92
28	8	92
29	8	92
30	9	91
31	10	90

	Rain chance (%)
1	87
2	88
3	88
4	88
5	88
6	89
7	89
8	89
9	89
10	89
11	89
12	89
13	89
14	90
15	89
16	89
17	89
18	89
19	89
20	88
21	88
22	87
23	87
24	87
25	86
26	86
27	86
28	85
29	85
30	85
31	85

	Oppressive (%)	Miserable (%)
1	34	66
2	34	66
3	35	65
4	36	64
5	36	64
6	37	63
7	38	62
8	39	61
9	40	60
10	41	59
11	42	58
12	43	57
13	45	55
14	46	54
15	47	53
16	48	52
17	49	51
18	50	50
19	51	49
20	52	48
21	52	48
22	53	47
23	53	47
24	54	46
25	54	46
26	54	46
27	54	46
28	54	46
29	54	46
30	54	46
31	54	46

	Avg high (°C)	Avg low (°C)
1	30	24
2	30	24
3	30	24
4	30	24
5	30	24
6	30	24
7	30	24
8	30	24
9	30	24
10	30	24
11	30	24
12	30	24
13	30	24
14	30	24
15	30	24
16	30	24
17	30	24
18	30	24
19	30	24
20	30	24
21	30	24
22	30	24
23	30	24
24	30	24
25	30	24
26	30	24
27	30	24
28	30	24
29	30	24
30	30	24
31	30	24

	Clearer (%)	Cloudier (%)
1	11	89
2	11	89
3	11	89
4	11	89
5	10	90
6	10	90
7	10	90
8	9	91
9	8	92
10	8	92
11	8	92
12	8	92
13	8	92
14	7	93
15	7	93
16	7	93
17	7	93
18	7	93
19	7	93
20	7	93
21	8	92
22	7	93
23	7	93
24	7	93
25	7	93
26	8	92
27	8	92
28	8	92
29	8	92
30	9	91
31	10	90

	Rain chance (%)
1	87
2	88
3	88
4	88
5	88
6	89
7	89
8	89
9	89
10	89
11	89
12	89
13	89
14	90
15	89
16	89
17	89
18	89
19	89
20	88
21	88
22	87
23	87
24	87
25	86
26	86
27	86
28	85
29	85
30	85
31	85

	Oppressive (%)	Miserable (%)
1	34	66
2	34	66
3	35	65
4	36	64
5	36	64
6	37	63
7	38	62
8	39	61
9	40	60
10	41	59
11	42	58
12	43	57
13	45	55
14	46	54
15	47	53
16	48	52
17	49	51
18	50	50
19	51	49
20	52	48
21	52	48
22	53	47
23	53	47
24	54	46
25	54	46
26	54	46
27	54	46
28	54	46
29	54	46
30	54	46
31	54	46