Miri weather in September

In September, Miri has daytime highs averaging 29 °C, nights around 25 °C, with 25 wet days, and a sea temperature of 30 °C. Figures are 1991–2020 climate normals.

  1. Jan 26°
  2. Feb 26°
  3. Mar 26°
  4. Apr 27°
  5. May 27°
  6. Jun 27°
  7. Jul 27°
  8. Aug 27°
  9. Sep 27°
  10. Oct 26°
  11. Nov 26°
  12. Dec 26°

Daily temperatures through September

22°27°32°18152229
Daily highDaily low Day of month on the horizontal axis. Highs peak at 29.6 °C and lows bottom out at 24.2 °C.

How September develops

Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.

DaysAvg highAvg lowChance of rain
1–10 September29.1 °C24.5 °C83 %
11–20 September29.4 °C24.7 °C80 %
21–30 September29.3 °C24.6 °C82 %
0%50%100%151015202530
Chance of a wet day (over 1 mm) by date in September. Wettest date over the 30 years: September 4, at 90 %. Single dates are noisy — read the shape, not the spikes.

What to expect

Measure Typical September Share of the month
Days above 25 °C 30 of 30 100 %
Days above 30 °C 5.4 of 30 18 %
Days below 0 °C 0 of 30 0 %
Days with more than 1 mm rain 25 of 30 82 %

Conditions in September

MeasureAverage
Mean temperature 27 °C
Record high (1991–2020) 33 °C
Record low (1991–2020) 22 °C
Relative humidity 85 %
Wind speed 13 km/h
Cloud cover 86 %

Where Miri ranks in September

RankingPositionValue
Warmest sea temperatures in Asia in September31stof 5030 °C
Warmest sea temperatures in the world in September47thof 5030 °C

September compared with the months around it

Month Avg high Rainfall Cloud
July 29.4 °C 195 mm 83 %
August 29.4 °C 198 mm 84 %
September 29.3 °C 211 mm 86 %
October 28.7 °C 293 mm 90 %
November 28.6 °C 296 mm 90 %

See all twelve months for Miri

Nearby destinations in September

Destination Avg high Wet days Sea
Miri 29 °C 25 30
Bandar Seri Begawan 30 °C 23 30
Bintulu 30 °C 25 30
Kota Kinabalu 29 °C 22 30
Sibu 30 °C 25
Tarakan 29 °C 27 29
Tawau 29 °C 27 29
Sandakan 30 °C 27 30
Kuching 30 °C 25

QuestionsSeptember in Miri, answered

How warm is Miri in September?

Daily highs average 29 °C and nights fall to about 25 °C, a spread of 4.7 °C between afternoon and dawn. That makes September the 6th warmest month of the year here.

Does it rain much in Miri in September?

September averages 211 mm of rain, spread over about 25 of the 30 days — 82 % of the month. Cloud cover averages 86 % of the sky.

Is the sea warm enough to swim in September?

The sea averages 30 °C off Miri in September. Most people find water below 20 °C bracing and above 25 °C comfortable for a long swim; this figure is a monthly surface average, so a sheltered bay on a still afternoon can be warmer.

How long are the days in September?

Miri averages 12 hours between sunrise and sunset in September. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.

Data sources and method

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

Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. 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.