Dumai, Indonesia climate

As Tropical savanna (dry summer)

Dumai has a remarkably steady tropical climate (Tropical savanna (dry summer), Köppen As). The hottest month is May with an average daily high near 34°C, while the coldest is December averaging around 23°C at night. Precipitation totals about 1094 mm a year and is strongly seasonal — November alone averages 201 mm while June barely receives 38 mm.

☀️ All year

Hot

Daytime highs near 34°C most of the year.

About 209 days a year above 32 °C

🌙 Nights

Stays warm

Even the coolest nights stay near 23°C.

🌧️ Rain

Wet

About 1094 mm of rain a year.

Wettest in November

⛅ Sky & trend

Often grey

Overcast skies dominate much of the year.

+0.7 °C vs 50 years ago

Temperature & precipitation

Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figures

Clear vs cloudy days

Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day counts

Dumai climate normals (1991–2020)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°C)	32	32	33	33	34	33	33	33	33	33	32	32
Avg temp (°C)	27	28	28	28	28	28	28	28	28	28	28	27
Avg low (°C)	23	23	23	23	23	23	23	23	23	23	23	23
Precipitation (mm)	91	89	99	85	91	38	46	66	81	125	201	83

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Avg high (°C)	32	32	33	33	34	33
Avg temp (°C)	27	28	28	28	28	28
Avg low (°C)	23	23	23	23	23	23
Precipitation (mm)	91	89	99	85	91	38

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°C)	33	33	33	33	32	32
Avg temp (°C)	28	28	28	28	28	27
Avg low (°C)	23	23	23	23	23	23
Precipitation (mm)	46	66	81	125	201	83

How often — frequency of weather events

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	2	2	3	3	2	1	1	2	2	3	4	3
Days with high ≥ 32°C (days)	13	15	19	20	19	19	20	19	18	19	16	12

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Days with measurable rain (days)	2	2	3	3	2	1
Days with high ≥ 32°C (days)	13	15	19	20	19	19

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	1	2	2	3	4	3
Days with high ≥ 32°C (days)	20	19	18	19	16	12

Sky & atmosphere

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	88	84	83	83	81	76	76	80	84	88	91	91
Clear days (≤ 30% cloud)	0.2	0.4	0.4	0.4	0.5	1	1	0.9	0.4	0.1	0.0	0.1
Partly cloudy days (30–70%)	4	5	6	6	7	9	9	7	5	4	2	2
Cloudy days (≥ 70%)	27	23	25	24	24	20	21	24	25	27	28	29
Relative humidity (%)	90	89	90	91	92	91	90	90	89	90	91	92
Wind speed (mph)	0.3	0.3	0.4	0.4	0.4	0.4	0.3	0.3	0.3	0.3	0.3	0.3

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Cloud cover (%)	88	84	83	83	81	76
Clear days (≤ 30% cloud)	0.2	0.4	0.4	0.4	0.5	1
Partly cloudy days (30–70%)	4	5	6	6	7	9
Cloudy days (≥ 70%)	27	23	25	24	24	20
Relative humidity (%)	90	89	90	91	92	91
Wind speed (mph)	0.3	0.3	0.4	0.4	0.4	0.4

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	76	80	84	88	91	91
Clear days (≤ 30% cloud)	1	0.9	0.4	0.1	0.0	0.1
Partly cloudy days (30–70%)	9	7	5	4	2	2
Cloudy days (≥ 70%)	21	24	25	27	28	29
Relative humidity (%)	90	90	89	90	91	92
Wind speed (mph)	0.3	0.3	0.3	0.3	0.3	0.3

Methodology & sources

Temperature & precipitation — 1991–2020 normals computed from 26 years of daily observations at Sultan Syarif Kasim II, a weather station, about 134 km from the city centre. The underlying daily records come from NOAA's global station network.

Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.

How we build these numbers →