Bontang climate — normals and trends
Bontang (Indonesia) has a tropical rainforest climate (Af) under the Köppen-Geiger classification. Its mean annual temperature is 26.3 °C and it receives 2,127 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is May (26.6 °C on average) and the coldest is January (26.0 °C). Rainfall peaks in December.
Bontang averages 0 frost days, 30 hot days (≥ 30 °C) and 305 rainy days per year.
Bontang has warmed by +1.5 °C between 1940 and 2025, or +0.17 °C per decade. This trend is statistically significant.
The hottest day of the period reached 32.4 °C (on 10 March 2016) and the coldest 22.0 °C (on 4 August 1949).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
BontangEast Kalimantan
- coords
- 0.13°, 117.49°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
26.3°C
Average daily high
28.6°C
Average daily low
24.5°C
Annual rainfall
2,127mm
Sunshine / day
10.0h
Mean relative humidity
85%
Average peak wind
12.7km/h
Seasonal range
0.6°C
Frost days (< 0 °C)
0 d/yr
Hot days (≥ 30 °C)
30 d/yr
Rainy days (≥ 1 mm)
305 d/yr
Annual snowfall
0.0 cm
Average feels-like high
34.2 °C
Average feels-like low
28.7 °C
Average peak gust
23.5 km/h
Tropical nights (≥ 20 °C)
365 d/yr
Solar radiation
17.6 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.5 °C
since 1940
+0.2 °C per decade · r² = 0.75 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
32.4 °C
10 March 2016
Coldest day
22.0 °C
4 August 1949
Wettest day
120 mm
6 January 1949
Windiest day
27.8 km/h
8 September 1940
Strongest gust
50.8 km/h
29 November 1955
Hottest feels-like
39.8 °C
15 October 2023
Coldest feels-like
22.9 °C
4 August 1949
Sunniest day
12.0 h
21 September 1940
Normals computed over complete calendar years 1940–2025.
A specific year
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Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 29.0 °C | +0.6 °C | 327 mm | +133 mm |
| Feb | 29.5 °C | +1.0 °C | 230 mm | +69 mm |
| Mar | 29.2 °C | +0.5 °C | 306 mm | +115 mm |
| Apr | 29.1 °C | +0.3 °C | 330 mm | +130 mm |
| May | 29.7 °C | +0.9 °C | 342 mm | +152 mm |
| Jun | 29.2 °C | +0.7 °C | 162 mm | -2 mm |
| Jul | 29.7 °C | +1.3 °C | 110 mm | -34 mm |
| Aug | 29.0 °C | +0.5 °C | 192 mm | +58 mm |
| Sep | 29.6 °C | +0.9 °C | 224 mm | +87 mm |
| Oct | 29.8 °C | +0.9 °C | 185 mm | +15 mm |
| Nov | 29.7 °C | +1.0 °C | 303 mm | +93 mm |
| Dec | 29.5 °C | +1.0 °C | 264 mm | +29 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Bontang?
Bontang has a tropical rainforest climate (Köppen Af). Over 1940-2025, the average annual temperature is 26.3 °C and it receives 2,127 mm of precipitation per year.
What is the hottest day ever recorded in Bontang?
The hottest day measured in Bontang between 1940 and 2025 was 10 March 2016, reaching 32.4 °C.
What is the coldest day in Bontang?
The coldest day measured in Bontang between 1940 and 2025 was 4 August 1949, at 22.0 °C.
Does it snow in Bontang?
Almost never: Bontang sees virtually no snow, with about 0 frost days per year.
Has the climate of Bontang warmed?
Yes: Bontang warmed by +1.5 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Bontang?
The wettest day measured in Bontang between 1940 and 2025 was 6 January 1949, with 120 mm of rain in 24 hours.
What was the windiest day in Bontang?
The windiest day measured in Bontang between 1940 and 2025 was 8 September 1940, with winds reaching 27.8 km/h.
What is the warmest month in Bontang?
The warmest month in Bontang is May (26.6 °C on average); the coldest is January (26.0 °C).
How much does it rain in Bontang?
Bontang receives on average 2,127 mm of precipitation per year, spread over about 305 rainy days.
Is it sunny in Bontang?
Bontang gets on average 10.0 hours of sunshine per day, roughly 3,650 hours per year over 1940-2025.
Are there tropical nights in Bontang?
Yes: Bontang has on average 365 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Bontang?
In Bontang, between 1940 and 2025, the highest apparent temperature reached 39.8 °C on 15 October 2023, and the lowest was 22.9 °C on 4 August 1949.
Compare Bontang with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Bontang