Sandakan has a tropical rainforest climate. It is hot all year round, with little seasonal variation in temperatures. It’s also pretty wet all year round with high levels of humidity – it is a rainforest, after all. The driest time is in April where you can expect average daily highs of 32°C, with overnight lows of 24°C. It’s hot, sticky and humid, but in terms of actual rainfall you will probably just see a few thundery downpours rather than anything too prolonged.
The best time of year for viewing turtles on Turtle Island is July. The best time to view Orang Utans is between April and November, as the trees are in fruit and the Orang Utans will come lower down in the forest. Between April and November, average daily highs remain at around 32°C, with overnight lows of 24°C. Rain increases as you move towards November, but as ever in the tropics you’ll find that most of the rain comes in torrential downpours in the afternoon or early evening.