If you're thinking of visiting Borneo the start of the dry season (if you can have one in the rainforest) is May and opens the window to the best time to visit Borneo for the country's wildlife areas. Towards the end of May it's the start of the fruiting season, which is the ideal time to see orangutans and other animals swinging through the trees. The local guides know which trees come into fruit early and can amaze you by spotting animals whist cruising down the Kinabatangan River.
This dry weather continues right through to the end of September and you are likely to see a range of animals through these months, especially the odd looking proboscis monkeys which roust at nightfall close to the rivers. Sukau is particularly abundant with these funny characters.
Pygmy elephants are rare to see, but your best chance is during the dry season when they venture to the river or known watering holes. They often use roads as a short cut through the rainforest reserves of Tabin and Danum Valley and this can present your best chance of seeing them.
The elusive western tarsier and even rarer clouded leopard are not something to base your trip on seeing, but you have a greater chance during the dry season and in areas of secondary rainforest such as Deramakot or Tabin.
The dry season is also the start of turtle nesting season when you have a good chance of seeing the mothers laying their eggs or even watching the little ones struggle down the beach into the water.
For those that love bird life a combination of Tabin and Danum in the summer is ideal as you can utilise the canopy walks to observe the amazing hornbills. You also get whale sharks off the east coast in March through to April.
The months of June and September are perfect for couples and the school holidays in July and August mean families get the perfect mix of good weather, amazing animals sightings and stunning beaches.
The summer months provide the clearest visibility for diving and, should the foreign office change its advice about visiting the islands around Sipadan, you will have easy access to some of the best scuba diving in the world!