Dumai weather in January

In January, Dumai sees average daytime highs of 31°C and overnight lows near 24°C, with 201 mm of rain across 21.3 wet days and about 11.9 hours of daylight. It is the 11th-warmest and 8th-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 6% of the time in January, and the air most often feels miserable.

Daylight stretches from about 11 h 54 min at the start of January to 11 h 54 min by month's end. Set against the rest of the year, January is Dumai's 6th-clearest and 1st-windiest month. For the whole year in context, see Dumai's year-round climate.

Daytime high
31°
11th warmest
Overnight low
24°
7th coldest
Rainfall
201 mm
21.3 wet days
Daylight
11 h 54 min
6:26 AM – 6:21 PM
Cloud cover
83%
6th clearest
Wind
7 km/h
1st windiest
Solar energy
4.86 kWh/m²
Travel score
3.3
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 January

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 31°C through the month.

A typical January 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, January runs on par with December and about 1°C cooler than February.

20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
13024
23124
33124
43124
53124
63124
73124
83124
93124
103124
113124
123124
133124
143124
153124
163124
173124
183124
193124
203124
213124
223124
233124
243124
253124
263124
273124
283124
293124
303124
313125

How January really feels in Dumai

Once humidity and wind are folded in, January 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 January is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Dumai weather by month

How January compares with the rest of the year at a glance. January is the 11th-warmest and 8th-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 January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 6% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 9% of January, with mostly cloudy or overcast conditions the remaining 84%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
11387
21387
31486
41486
51585
61585
71684
81684
91783
101783
111783
121783
131684
141684
151585
161585
171684
181684
191684
201585
211585
221585
231585
241585
251585
261585
271585
281684
291684
301684
311882

Chance of precipitation in January

Any precipitation

Dumai gets around 201 mm of rain over 21.3 wet days in January. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 69% and peaks near 79% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
179
278
377
476
575
674
773
872
971
1070
1170
1269
1369
1468
1567
1667
1766
1866
1966
2066
2165
2265
2365
2465
2565
2665
2765
2864
2964
3063
3163

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, January lands in the miserable band about 60% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Muggy (%)Oppressive (%)Miserable (%)
103070
203169
303268
403268
503367
603466
703466
803565
903664
1003763
1103763
1213861
1313861
1413960
1513960
1614059
1714158
1814158
1914257
2014257
2114257
2214356
2314356
2424355
2524454
2624454
2724553
2824652
2924751
3024850
3124950

Wind in January

Winds average 7 km/h in January, the windiest month of the year.

Across January, daily wind ranges from about 6 km/h on the calmest days to 7 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
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in January

DaylightNight

Daylight runs from about 11 h 54 min at the start of January 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 January. Sunrise moves from 6:20 AM to 6:30 AM, and sunset from 6:15 PM to 6:25 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.96:206:15
211.96:216:15
311.96:216:15
411.96:226:16
511.96:226:16
611.96:226:17
711.96:236:17
811.96:236:18
911.96:246:18
1011.96:246:19
1111.96:246:19
1211.96:256:19
1311.96:256:20
1411.96:256:20
1511.96:266:21
1611.96:266:21
1711.96:266:21
1811.96:276:22
1911.96:276:22
2011.96:276:22
2111.96:286:23
2211.96:286:23
2311.96:286:23
2411.96:286:24
2511.96:296:24
2611.96:296:24
2711.96:296:24
2811.96:296:25
2911.96:296:25
3011.96:306:25
3111.96:306:25

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 4.86 kWh/m².

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 — January's 4.86 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
14.5Bright
24.5Bright
34.5Bright
44.6Bright
54.6Bright
64.6Bright
74.7Bright
84.7Bright
94.7Bright
104.8Bright
114.8Bright
124.8Bright
134.8Bright
144.9Bright
154.9Bright
164.9Bright
174.9Bright
184.9Bright
195.0Bright
205.0Bright
215.0Bright
225.0Bright
235.0Bright
245.0Bright
255.0Bright
265.0Bright
275.0Bright
285.1Bright
295.1Bright
305.1Bright
315.1Bright
Planning a trip in January

Is January a good time to visit Dumai?

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

3.3
Sightseeing
1st-best month of the year
4.7
Beach & pool
2nd-best month of the year

January is a weaker month for outdoor sightseeing in Dumai.

What to pack for Dumai in January

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

In January, Dumai sees daytime highs around 31°C and nights near 24°C. Pack light clothes and rain gear. Worth having: sun protection. About 21 days see rain.

light clothesrain gearsun protection

Sea temperature near Dumai in January

The nearest coast averages about 29°C in January — 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 January

LowModerateHighVery highExtreme

Clear-sky midday UV in January 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 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 January

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where January 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
January 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).