Bukit Mertajam weather in December
In December, Bukit Mertajam has daytime highs averaging 29 °C, nights around 23 °C, with 23 wet days, and a sea temperature of 29 °C. Figures are 1991–2020 climate normals.
- 28.9°C Average high
- 23.1°C Average low
- 23days Wet days
- 259mm Rainfall
- 29.2°C Sea temperature
- 12h Daylight
Daily temperatures through December
How December 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.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 December | 28.9 °C | 23.3 °C | 84 % |
| 11–20 December | 28.9 °C | 23.2 °C | 78 % |
| 21–31 December | 29.0 °C | 22.9 °C | 66 % |
- Rain is most likely over days 1–10 of December (84 % of days) and least likely over days 21–31 (66 %).
What to expect
| Measure | Typical December | Share of the month |
|---|---|---|
| Days above 25 °C | 31 of 31 | 100 % |
| Days above 30 °C | 4.0 of 31 | 13 % |
| Days below 0 °C | 0 of 31 | 0 % |
| Days with more than 1 mm rain | 23 of 31 | 76 % |
Conditions in December
| Measure | Average |
|---|---|
| Mean temperature | 26 °C |
| Record high (1991–2020) | 32 °C |
| Record low (1991–2020) | 20 °C |
| Relative humidity | 85 % |
| Wind speed | 8.2 km/h |
| Cloud cover | 83 % |
Where Bukit Mertajam ranks in December
| Ranking | Position | Value |
|---|---|---|
| Warmest sea temperatures in Asia in December | 30thof 50 | 29 °C |
| Warmest sea temperatures in the world in December | 37thof 50 | 29 °C |
December compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| January | 29.6 °C | 168 mm | 74 % |
| February | 30.5 °C | 131 mm | 69 % |
| October | 28.8 °C | 337 mm | 90 % |
| November | 28.8 °C | 368 mm | 88 % |
| December | 28.9 °C | 259 mm | 83 % |
See all twelve months for Bukit Mertajam
- December is the 10th warmest month here.
- It is the 10th driest month of the year.
- It ranks 5th for least cloud cover.
- Days last about 12 hours from sunrise to sunset.
- It rains on 23 of 31 days — 76 % of the month.
- Nights are about 5.8 °C cooler than the middle of the day.
- The hottest December day on record since 1991 reached 32 °C, 2.9 °C above the usual daytime high.
- Beach score: 68 / 100 — see how this is calculated.
Nearby destinations in December
| Destination | Avg high | Wet days | Sea |
|---|---|---|---|
| Bukit Mertajam | 29 °C | 23 | 29 |
| Kulim | 29 °C | 24 | – |
| George Town | 29 °C | 20 | 29 |
| Paya Terubong | 28 °C | 21 | 29 |
| Kota Kuala Muda | 29 °C | 20 | 29 |
| Sungai Petani | 29 °C | 18 | 29 |
| Taiping | 29 °C | 26 | 29 |
| Alor Setar | 29 °C | 15 | 29 |
QuestionsDecember in Bukit Mertajam, answered
How warm is Bukit Mertajam in December?
Daily highs average 29 °C and nights fall to about 23 °C, a spread of 5.8 °C between afternoon and dawn. That makes December the 12th warmest month of the year here.
Does it rain much in Bukit Mertajam in December?
December averages 259 mm of rain, spread over about 23 of the 31 days — 76 % of the month. Cloud cover averages 83 % of the sky.
Is the sea warm enough to swim in December?
The sea averages 29 °C off Bukit Mertajam in December. 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 December?
Bukit Mertajam averages 12 hours between sunrise and sunset in December. 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
- 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
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.