Dumai weather in December

In December, Dumai sees average daytime highs of 31°C and overnight lows near 24°C, with 343 mm of rain across 27.7 wet days and about 11.9 hours of daylight. It is the 12th-warmest and 2nd-wettest month of the year here.

Day-to-day highs hold fairly steady near 31°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 11 h 54 min at the start of December to 11 h 54 min by month's end. Set against the rest of the year, December is Dumai's 11th-clearest and 3rd-windiest month. For the whole year in context, see Dumai's year-round climate.

Daytime high
31°
12th warmest
Overnight low
24°
7th coldest
Rainfall
343 mm
27.7 wet days
Daylight
11 h 54 min
6:13 AM – 6:08 PM
Cloud cover
91%
11th clearest
Wind
6 km/h
3rd windiest
Solar energy
4.21 kWh/m²
Travel score
2.7
out of 10

Dumai is city in Riau Province, Indonesia.

Density
202/km²
people per km²
Founded
1999

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 31°C through the month.

A typical December day in Dumai reaches about 31°C in the afternoon and slips back to 24°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 29°C and 32°C. Set against its neighbours, December runs on par with November and on par with January.

20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
13124
23124
33124
43124
53124
63124
73124
83124
93124
103124
113124
123124
133124
143124
153124
163024
173024
183024
193024
203024
213024
223024
233024
243024
253024
263024
273024
283024
293024
303024
313024

How December really feels in Dumai

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.

Dumai weather by month

How December compares with the rest of the year at a glance. December is the 12th-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan31° / 24°20121.311.93.3
Feb32° / 25°12316.811.93.2
Mar32° / 25°21725.1122.5
Apr32° / 25°24927.6122.2
May32° / 25°22426.312.12.3
Jun32° / 25°15621.312.12.7
Jul32° / 24°16220.412.13.0
Aug32° / 24°1952412.12.7
Sep32° / 24°25326.1122.5
Oct31° / 24°30828.2122.4
Nov31° / 24°38728.511.92.4
Dec31° / 24°34327.711.92.7

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 3% of December, with mostly cloudy or overcast conditions the remaining 94%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
1595
2595
3595
4595
5595
6496
7496
8595
9595
10595
11496
12496
13496
14496
15496
16496
17496
18496
19496
20496
21595
22595
23694
24694
25694
26793
27991
281090
291090
301189
311288

Chance of precipitation in December

Any precipitation

Dumai gets around 343 mm of rain over 27.7 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 89% and peaks near 93% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%100%151015202531
Rain chance (%)
193
292
392
492
592
691
791
891
991
1091
1191
1291
1391
1491
1591
1690
1790
1890
1990
2090
2189
2289
2388
2487
2586
2686
2785
2883
2982
3081
3180

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 81% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Oppressive (%)Miserable (%)
11189
21288
31288
41387
51387
61486
71486
81486
91585
101585
111585
121585
131684
141684
151783
161783
171882
181981
192080
202080
212179
222278
232377
242476
252575
262674
272773
282872
292872
302971
313070

Wind in December

Winds average 6 km/h in December.

Across December, daily wind ranges from about 6 km/h on the calmest days to 6 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (km/h)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm
316calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 11 h 54 min at the start of December to 11 h 54 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 6:07 AM to 6:20 AM, and sunset from 6:01 PM to 6:15 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.96:076:01
211.96:076:02
311.96:076:02
411.96:086:02
511.96:086:03
611.96:096:03
711.96:096:04
811.96:106:04
911.96:106:04
1011.96:106:05
1111.96:116:05
1211.96:116:06
1311.96:126:06
1411.96:126:07
1511.96:136:07
1611.96:136:08
1711.96:146:08
1811.96:146:08
1911.96:156:09
2011.96:156:09
2111.96:166:10
2211.96:166:10
2311.96:176:11
2411.96:176:11
2511.96:176:12
2611.96:186:12
2711.96:186:13
2811.96:196:13
2911.96:196:14
3011.96:206:14
3111.96:206:15

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 4.21 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 4.21 kWh/m² to a high of 5.49 kWh/m² in February across the year — December's 4.21 kWh/m² sits near the bottom.

012345151015202531
Solar energy (kWh/m²)Level
14.3Bright
24.3Bright
34.2Bright
44.2Bright
54.2Bright
64.2Bright
74.2Bright
84.2Bright
94.2Bright
104.2Bright
114.2Bright
124.2Bright
134.2Bright
144.2Bright
154.2Bright
164.2Bright
174.2Bright
184.2Bright
194.2Bright
204.2Bright
214.2Bright
224.2Bright
234.2Bright
244.2Bright
254.3Bright
264.3Bright
274.3Bright
284.3Bright
294.4Bright
304.4Bright
314.4Bright
Planning a trip in December

Is December a good time to visit Dumai?

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

2.7
Sightseeing
4th-best month of the year
3.9
Beach & pool
7th-best month of the year

December is a weaker month for outdoor sightseeing in Dumai.

What to pack for Dumai in December

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

In December, Dumai sees daytime highs around 31°C and nights near 24°C. Pack light clothes and rain gear. About 28 days see rain.

light clothesrain gear

Sea temperature near Dumai 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 48 km away) is warmest in May 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
Oct30Tropical
Nov29Tropical
Dec29Tropical

UV index in Dumai 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 Dumai peaks around February 17 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 20 at about 10 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highExtremeFeb 17UV 14Jun 20UV 10
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar13Extreme
Apr13Extreme
May12Extreme
Jun10Very high
Jul10Extreme
Aug12Extreme
Sep13Extreme
Oct14Extreme
Nov11Extreme
Dec11Extreme

Air quality in Dumai 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 Dumai is worst in September — around 43 µg/m³ PM2.5 (poor), about 2.9× the cleanest month (December, 15 µg/m³).

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorModerateSep 943 µg/m³Dec 1015 µg/m³
PM2.5 (µg/m³)Level
Jan18Moderate
Feb31Moderate
Mar36Poor
Apr26Moderate
May20Moderate
Jun21Moderate
Jul37Poor
Aug42Poor
Sep43Poor
Oct30Moderate
Nov15Moderate
Dec15Moderate
Location & terrain

Where is Dumai?

Dumai sits at 1.7°N, 101.4°E, 7 m above sea level, in Indonesia. The nearest listed city is Balai Pungut, 70 km away.

Topography around Dumai

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

Within 3 km, the terrain around Dumai has only modest variations in elevation — a maximum elevation change of 27 m around an average of 5 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 77 m.

The land around Dumai is covered by artificial surfaces (51%) and trees (31%) within 3 km, trees (66%) and water (20%) within 16 km, and trees (64%) and water (29%) within 80 km.

3 km
27 m
16 km
53 m
80 km
77 m
treesshrubsgrasslandartificial surfacesbare terrainwatermangroves
December weather nearby: Balai Pungut 70 km · Kampung Teluk Kemang 100 km · Sungai Udang 103 km · Port Dickson 103 km · Klebang Besar 104 km · Bukit Rambai 105 km · Malacca 106 km · Kampong Masjid Tanah 107 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 Dumai (1.6671°, 101.4432°, elevation 7 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).