Pematangsiantar weather in December

In December, Pematangsiantar sees average daytime highs of 28°C and overnight lows near 21°C, with 315 mm of rain across 29.6 wet days and about 11.8 hours of daylight. It is the 12th-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 28°C through the month. The sky is clear or mostly clear about 0% of the time in December, and the air most often feels oppressive.

Daylight stretches from about 11 h 48 min at the start of December to 11 h 48 min by month's end. Set against the rest of the year, December is Pematangsiantar's 10th-clearest and 2nd-windiest month. For the whole year in context, see Pematangsiantar's year-round climate.

Daytime high
28°
12th warmest
Overnight low
21°
4th coldest
Rainfall
315 mm
29.6 wet days
Daylight
11 h 48 min
6:25 AM – 6:15 PM
Cloud cover
93%
10th clearest
Wind
4 km/h
2nd windiest
Solar energy
3.99 kWh/m²
Travel score
3.3
out of 10

Pematangsiantar is city in North Sumatra Province, Indonesia.

Density
3,491/km²
people per km²
Founded
1871

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 28°C through the month.

A typical December day in Pematangsiantar reaches about 28°C in the afternoon and slips back to 21°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 26°C and 29°C. Set against its neighbours, December runs on par with November and on par with January.

20°23°25°28°30°151015202531
Avg high (°C)Avg low (°C)
12821
22821
32821
42821
52821
62821
72821
82821
92821
102821
112821
122821
132821
142821
152821
162821
172821
182821
192821
202821
212821
222821
232821
242821
252821
262821
272821
282821
292821
302821
312821

How December really feels in Pematangsiantar

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

December sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Pematangsiantar weather by month

How December compares with the rest of the year at a glance. December is the 12th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 21°24027.911.83.5
Feb28° / 21°18924.111.93.4
Mar29° / 21°21726.5123.3
Apr29° / 22°24928.612.12.8
May30° / 22°26529.212.12.8
Jun30° / 22°23127.112.23.0
Jul29° / 21°23726.712.23.2
Aug29° / 21°27428.812.13.0
Sep29° / 21°36129.4122.9
Oct28° / 21°37530.211.92.9
Nov28° / 21°35129.411.93.2
Dec28° / 21°31529.611.83.3

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 0% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 2% of December, with mostly cloudy or overcast conditions the remaining 98%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
1298
2298
3298
4298
5298
6298
7298
8298
9298
10298
11298
12298
13199
14199
15199
16199
17199
18199
19199
20199
21199
22298
23298
24397
25397
26397
27397
28496
29496
30595
31595

Chance of precipitation in December

Any precipitation

Pematangsiantar gets around 315 mm of rain over 29.6 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 95% and peaks near 97% on the wettest days.

0%20%40%60%80%100%151015202531
Rain chance (%)
197
297
397
497
597
697
797
896
996
1096
1195
1295
1395
1495
1595
1695
1795
1895
1995
2095
2195
2295
2395
2495
2595
2695
2795
2894
2994
3094
3193

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 74% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Muggy (%)Oppressive (%)
11684
21783
31882
41882
51981
61981
72080
82080
92080
102179
112179
122179
132278
142278
152377
162476
172575
182674
192773
202872
212971
223070
233169
243268
253367
263466
273565
283664
293763
303862
313862

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

0246810151015202531
Wind speed (km/h)Feels
14calm
24calm
34calm
44calm
54calm
64calm
74calm
84calm
94calm
104calm
114calm
124calm
134calm
144calm
154calm
164calm
174calm
184calm
194calm
204calm
214calm
224calm
234calm
244calm
254calm
264calm
274calm
284calm
294calm
304calm
314calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 11 h 48 min at the start of December to 11 h 48 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 6:18 AM to 6:32 AM, and sunset from 6:09 PM to 6:22 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.86:186:09
211.86:196:09
311.86:196:09
411.86:206:10
511.86:206:10
611.86:206:11
711.86:216:11
811.86:216:11
911.86:226:12
1011.86:226:12
1111.86:236:13
1211.86:236:13
1311.86:246:13
1411.86:246:14
1511.86:256:14
1611.86:256:15
1711.86:256:15
1811.86:266:16
1911.86:266:16
2011.86:276:17
2111.86:276:17
2211.86:286:18
2311.86:286:18
2411.86:296:19
2511.86:296:19
2611.86:306:19
2711.86:306:20
2811.86:316:20
2911.86:316:21
3011.86:326:21
3111.86:326:22

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 3.99 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 3.99 kWh/m² to a high of 5.21 kWh/m² in March across the year — December's 3.99 kWh/m² sits near the bottom.

012345151015202531
Solar energy (kWh/m²)Level
14.0Moderate
24.0Moderate
34.0Moderate
44.0Moderate
54.0Moderate
64.0Moderate
74.0Moderate
84.0Moderate
94.0Moderate
104.0Moderate
114.0Moderate
124.0Moderate
134.0Bright
144.0Bright
154.0Bright
164.0Bright
174.0Bright
184.0Bright
194.0Bright
204.0Bright
214.0Bright
224.0Bright
234.0Bright
244.0Bright
254.1Bright
264.1Bright
274.1Bright
284.1Bright
294.2Bright
304.2Bright
314.2Bright
Planning a trip in December

Hazard calendar for Pematangsiantar

In seasonPeak

In December, Pematangsiantar sits inside its cyclone season. The full year is below, with each hazard's peak months called out.

Pematangsiantar sits in the North Indian Ocean cyclone zone; the season peaks May and October–November.

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

Is December a good time to visit Pematangsiantar?

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

3.3
Sightseeing
3rd-best month of the year
3.6
Beach & pool
9th-best month of the year

December is a weaker month for outdoor sightseeing in Pematangsiantar.

What to pack for Pematangsiantar in December

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

In December, Pematangsiantar sees daytime highs around 28°C and nights near 21°C. Pack light clothes and rain gear. About 30 days see rain.

light clothesrain gear

Sea temperature near Pematangsiantar in December

The nearest coast averages about 29°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 57 km away) is warmest in June at about 30°C and coldest in January near 29°C.

The water stays above 20°C all year — warm enough for a swim any month.

28°30°32°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan29Tropical
Feb29Tropical
Mar29Tropical
Apr30Tropical
May30Tropical
Jun30Tropical
Jul30Tropical
Aug30Tropical
Sep30Tropical
Oct29Tropical
Nov29Tropical
Dec29Tropical

UV index in Pematangsiantar in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 11 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Pematangsiantar peaks around February 21 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 20 at about 10 (extreme).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeFeb 21UV 15Jun 20UV 10
UV index (midday)Level
Jan13Extreme
Feb15Extreme
Mar14Extreme
Apr13Extreme
May12Extreme
Jun10Extreme
Jul11Extreme
Aug12Extreme
Sep14Extreme
Oct14Extreme
Nov11Extreme
Dec11Extreme

Air quality in Pematangsiantar 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 Pematangsiantar is worst in October — around 40 µg/m³ PM2.5 (poor), and holds fairly steady the rest of the year.

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorModeratePoorModerateOct 1039 µg/m³Dec 1729 µg/m³
PM2.5 (µg/m³)Level
Jan31Moderate
Feb35Moderate
Mar38Poor
Apr36Poor
May34Moderate
Jun33Moderate
Jul33Moderate
Aug34Moderate
Sep39Poor
Oct40Poor
Nov31Moderate
Dec29Moderate
Location & terrain

Where is Pematangsiantar?

Pematangsiantar sits at 3.0°N, 99.1°E, 388 m above sea level, in Indonesia. The nearest listed city is Pekan Bahapal, 21 km away.

Topography around Pematangsiantar

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

Within 3 km, the terrain around Pematangsiantar has only modest variations in elevation — a maximum elevation change of 130 m around an average of 382 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 1,193 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,429 m.

The land around Pematangsiantar is covered by artificial surfaces (56%) and trees (30%) within 3 km, trees (77%) within 16 km, and trees (70%) within 80 km.

3 km
130 m
16 km
1,193 m
80 km
2,429 m
treesgrasslandcroplandartificial surfaceswater
December weather nearby: Pekan Bahapal 21 km · Tebingtinggi 42 km · Pangururan 57 km · Kisaran 61 km · Tongging 61 km · Paropo 62 km · Kabanjahe 66 km · Berastagi 67 km

Indonesia travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / F
230 V · 50 Hz
Prices
≈ 29% of US
price level, 2025
GDP per capita
$5,060
2025
Happiness
5.6 / 10
World Happiness, 2025
Safe drinking water
30%
of population, 2024
Homicide rate
0.3
per 100k, 2022
Road deaths
11.3
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 471
Religion
Muslim 87%Protestant 8%Roman Catholic 3%Hindu 2%

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 Pematangsiantar (2.9595°, 99.0687°, elevation 388 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).