Sandakan boasts a year-around average temperature of 27.1°C, peaking at 27.4°C in May, its warmest month, and dipping to an average low of 26.9°C in January, February, July, the coolest. Rainfall averages at 256.3mm annually, with December seeing the heaviest showers and April being the driest month.
Month | Temperature (Celcius) | Rainfall (mm) |
| January | 26.9 | 451.1 |
| February | 26.9 | 269.7 |
| March | 27.1 | 183.9 |
| April | 27.2 | 111.8 |
| May | 27.4 | 144.8 |
| June | 27.2 | 196.8 |
| July | 26.9 | 184.9 |
| August | 27.1 | 230.9 |
| September | 27.2 | 237.0 |
| October | 27.2 | 252.2 |
| November | 27.1 | 349.0 |
| December | 27.0 | 463.5 |