Dumai climate

Name: Dumai
Address: ID

Dumai is warmest in May, with average highs of 30 °C, and coldest in January, when nights average 23 °C. November is the wettest month (389 mm) and February the driest (135 mm). Figures are 1991–2020 climate normals.

Across a full year Dumai averages 2,861 mm of rain and 365 days above 25 °C.

Indonesia · population 349,389 · 1991–2020 normals

Temperature below 0 °C to above 30 °C Rain band height is that month’s share of the wettest month

Warmest month May 30 °C
Coldest month January 23 °C
Driest month February 135 mm
Wettest month November 389 mm
Least cloud February 79 % cloud
Hottest on record May 36 °C
Coldest on record January 19 °C

What to expectDumai through the year

Dumai changes little through the year. Average daily highs stay between 29 and 30 °C, so no month stands out as a season in the way it would further from the equator.

Counted across a normal year, 365 days a year reach 25 °C, 176 of them reach 30 °C. The warmest reading in the 1991–2020 record is 36 °C, in May.

Rain is strongly seasonal. November averages 389 mm against 135 mm in February — 2.9 times as much. Planning around the dry months matters more here than planning around temperature.

Month by month

Month	Avg high	Rainfall	Cloud
January	28.9 °C	208 mm	83 %
February	29.7 °C	135 mm	79 %
March	30.2 °C	226 mm	81 %
April	30.3 °C	252 mm	87 %
May	30.5 °C	223 mm	86 %
June	30.5 °C	160 mm	80 %
July	30.3 °C	165 mm	79 %
August	30.3 °C	198 mm	82 %
September	30.2 °C	250 mm	84 %
October	29.8 °C	310 mm	90 %
November	29.1 °C	389 mm	93 %
December	28.7 °C	345 mm	91 %

Temperature month by month

Month	Avg high	Avg low	Mean	Record high	Record low	Days above 25 °C	Days above 30 °C
January	28.9 °C	23.3 °C	25.7 °C	32.6 °C	19.4 °C	31	4
February	29.7 °C	23.5 °C	26.2 °C	33.4 °C	21.6 °C	28	10
March	30.2 °C	23.8 °C	26.5 °C	33.9 °C	20.4 °C	31	18
April	30.3 °C	24.0 °C	26.5 °C	33.1 °C	21.8 °C	30	19
May	30.5 °C	24.3 °C	26.8 °C	36.4 °C	22.7 °C	31	21
June	30.5 °C	24.1 °C	26.8 °C	33.4 °C	21.8 °C	30	21
July	30.3 °C	23.8 °C	26.5 °C	33.6 °C	21.2 °C	31	20
August	30.3 °C	23.6 °C	26.4 °C	34.2 °C	22.3 °C	31	20
September	30.2 °C	23.6 °C	26.2 °C	33.6 °C	22.1 °C	30	18
October	29.8 °C	23.6 °C	26.1 °C	33.8 °C	21.6 °C	31	15
November	29.1 °C	23.4 °C	25.6 °C	32.5 °C	22.0 °C	30	6
December	28.7 °C	23.4 °C	25.5 °C	32.0 °C	21.3 °C	31	3

Rain, sun and wind month by month

Month	Rainfall	Wet days	Daylight	Cloud cover	Humidity	Wind
January	208 mm	21	12 h/day	83 %	87 %	10 km/h
February	135 mm	17	12 h/day	79 %	85 %	10 km/h
March	226 mm	25	12 h/day	81 %	87 %	9.4 km/h
April	252 mm	28	12 h/day	87 %	90 %	8.3 km/h
May	223 mm	27	12 h/day	86 %	90 %	8.2 km/h
June	160 mm	21	12 h/day	80 %	88 %	8.7 km/h
July	165 mm	21	12 h/day	79 %	87 %	9.3 km/h
August	198 mm	25	12 h/day	82 %	88 %	9.0 km/h
September	250 mm	26	12 h/day	84 %	89 %	8.5 km/h
October	310 mm	28	12 h/day	90 %	90 %	8.7 km/h
November	389 mm	29	12 h/day	93 %	92 %	8.8 km/h
December	345 mm	27	12 h/day	91 %	91 %	9.7 km/h

How Dumai compares

The same four figures for nearby destinations, so the numbers above have something to be read against. Summer high is the warmest month's average high; winter low is the coldest month's average low.

Destination	Summer high	Winter low	Rain per year	Days above 25 °C
Dumai	30 °C	23 °C	2,861 mm	365
Malacca · Malaysia	30 °C	24 °C	2,283 mm	365
Sepang · Malaysia	30 °C	23 °C	2,514 mm	365
Pekanbaru · Indonesia	30 °C	23 °C	2,490 mm	364
Seremban · Malaysia	30 °C	23 °C	2,642 mm	365
Muar · Malaysia	30 °C	24 °C	2,198 mm	364
Kajang · Malaysia	31 °C	22 °C	2,909 mm	365

Planning a trip? See the best time to visit Dumai.

QuestionsCommon questions about Dumai’s climate

When is the best time to visit Dumai?

That depends on what you want, so the honest answer is a comparison rather than a single month. January, November, December sit closest to 20 °C on average, May is the warmest month and February the driest. The month-by-month table above has the full picture.

How hot does Dumai get?

In May, the warmest month, daily highs average 30 °C. About 176 days a year pass 30 °C. The highest value in the 1991–2020 record is 36 °C.

How cold does it get in winter?

Nights average 23 °C in January, the coldest month. Freezing nights are not part of a normal year here.

Which month is wettest in Dumai?

November, averaging 389 mm over 29 days with rain. The driest month is February with 135 mm. The year as a whole averages 2,861 mm.

Are these figures a forecast?

No. They are 1991–2020 climate normals: the average of thirty years, which describes what a month is usually like in Dumai rather than what any particular week will bring. Individual years can differ substantially from the normal.

Data sources and method

ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
Open-Meteo — Open-Meteo.com. CC BY 4.0
NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
GeoNames — GeoNames.org. CC BY 4.0

Normal period: 1991–2020
Dataset version: era5-1991-2020-scores1.1
Last processed: 1 August 2026

Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: monthly rankings, daylight hours, beach and comfort scores. Full formulas are on the methodology page.

Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.