Bontang climate

Name: Bontang
Address: ID

Bontang is warmest in October, with average highs of 30 °C, and coldest in January, when nights average 24 °C. December is the wettest month (291 mm) and August the driest (164 mm). Figures are 1991–2020 climate normals.

Across a full year Bontang averages 2,776 mm of rain and 365 days above 25 °C.

Indonesia · population 194,606 · 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 October 30 °C
Coldest month January 24 °C
Driest month August 164 mm
Wettest month December 291 mm
Least cloud August 73 % cloud
Hottest on record April 40 °C
Coldest on record January 22 °C
Warmest sea May 30 °C

What to expectBontang through the year

Bontang 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, 75 of them reach 30 °C. The warmest reading in the 1991–2020 record is 40 °C, in April.

Rain is spread fairly evenly through the year, from 164 mm in August to 291 mm in December. There is no dry season to aim for.

The sea off Bontang is warmest in May at 30 °C and coldest in February at 29 °C. Sea temperature lags the air by a month or two, which is why late summer swims warmer than early summer at the same air temperature.

Month by month

Month	Avg high	Rainfall	Cloud
January	29.0 °C	249 mm	91 %
February	29.2 °C	225 mm	88 %
March	29.3 °C	265 mm	86 %
April	29.5 °C	280 mm	86 %
May	29.4 °C	249 mm	83 %
June	29.1 °C	221 mm	80 %
July	28.9 °C	181 mm	77 %
August	29.3 °C	164 mm	73 %
September	29.6 °C	172 mm	76 %
October	29.7 °C	216 mm	85 %
November	29.3 °C	263 mm	90 %
December	29.2 °C	291 mm	93 %

Temperature month by month

Month	Avg high	Avg low	Mean	Record high	Record low	Days above 25 °C	Days above 30 °C
January	29.0 °C	24.1 °C	26.1 °C	31.5 °C	22.2 °C	31	4
February	29.2 °C	24.2 °C	26.3 °C	32.1 °C	22.5 °C	28	5
March	29.3 °C	24.2 °C	26.4 °C	34.2 °C	22.6 °C	31	7
April	29.5 °C	24.4 °C	26.5 °C	39.7 °C	22.5 °C	30	8
May	29.4 °C	24.6 °C	26.6 °C	32.8 °C	22.8 °C	31	7
June	29.1 °C	24.3 °C	26.4 °C	31.7 °C	22.6 °C	30	4
July	28.9 °C	24.1 °C	26.2 °C	31.8 °C	22.2 °C	31	3
August	29.3 °C	24.2 °C	26.4 °C	31.8 °C	22.3 °C	31	6
September	29.6 °C	24.3 °C	26.6 °C	33.3 °C	22.4 °C	30	10
October	29.7 °C	24.4 °C	26.6 °C	37.0 °C	22.5 °C	31	11
November	29.3 °C	24.2 °C	26.3 °C	32.3 °C	22.8 °C	30	6
December	29.2 °C	24.1 °C	26.2 °C	36.7 °C	22.5 °C	31	5

Rain, sun and wind month by month

Month	Rainfall	Wet days	Daylight	Cloud cover	Humidity	Wind	Sea temp
January	249 mm	26	12 h/day	91 %	87 %	8.7 km/h	28.9 °C
February	225 mm	23	12 h/day	88 %	86 %	9.2 km/h	28.6 °C
March	265 mm	27	12 h/day	86 %	87 %	8.8 km/h	28.9 °C
April	280 mm	27	12 h/day	86 %	88 %	8.0 km/h	29.2 °C
May	249 mm	28	12 h/day	83 %	88 %	7.7 km/h	29.5 °C
June	221 mm	26	12 h/day	80 %	88 %	8.0 km/h	29.3 °C
July	181 mm	24	12 h/day	77 %	86 %	8.8 km/h	28.9 °C
August	164 mm	22	12 h/day	73 %	85 %	9.3 km/h	28.7 °C
September	172 mm	22	12 h/day	76 %	85 %	9.1 km/h	28.9 °C
October	216 mm	26	12 h/day	85 %	86 %	8.8 km/h	29.2 °C
November	263 mm	28	12 h/day	90 %	88 %	8.4 km/h	29.2 °C
December	291 mm	29	12 h/day	93 %	88 %	8.3 km/h	29.0 °C

How Bontang 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
Bontang	30 °C	24 °C	2,776 mm	365
Samarinda · Indonesia	31 °C	23 °C	2,992 mm	365
Loa Janan · Indonesia	31 °C	23 °C	2,917 mm	365
Balikpapan · Indonesia	29 °C	24 °C	2,499 mm	365
Palu · Indonesia	31 °C	24 °C	3,588 mm	365
Tarakan · Indonesia	29 °C	25 °C	3,063 mm	365
Toli-Toli · Indonesia	30 °C	23 °C	2,049 mm	365

Where Bontang ranks

Ranking	Position	Value
Warmest sea temperatures in Asia in January	30th of 50	29 °C
Warmest sea temperatures in the world in January	42nd of 50	29 °C
Warmest sea temperatures in Asia in December	44th of 50	29 °C

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

QuestionsCommon questions about Bontang’s climate

When is the best time to visit Bontang?

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

How hot does Bontang get?

In October, the warmest month, daily highs average 30 °C. About 75 days a year pass 30 °C. The highest value in the 1991–2020 record is 40 °C.

How cold does it get in winter?

Nights average 24 °C in January, the coldest month. Freezing nights are not part of a normal year here.

Which month is wettest in Bontang?

December, averaging 291 mm over 29 days with rain. The driest month is August with 164 mm. The year as a whole averages 2,776 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 Bontang 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
Data point: 0.132°, 117.485° (the coordinates the reanalysis values are taken for)
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.