1. Climate & Location
    Kota Kinabalu, the capital of Sabah, is located on the tropical island of Borneo.  Situated between 4 and 8 degrees north of the equator, the climate is always hot and humid.  It is, however, not too uncomfortable and after a few days you might not notice it so much. Virtually all enclosed establishments, plus all taxis, are air conditioned. 
  2. Minimum & Maximum Temperatures
    Temperatures are perpetually around 30 degrees Celsius, but can drop to the lower twenties when it rains, especially during the night.  Around the areas of Kundasang and Mt. Kinabalu, the interior, the climate is significantly cooler, whilst at the summit of Mt. Kinabalu (4095m) it's down right cold.
  3. Rain
    It can rain any time of year, although it is said that the wetter season is from October to February. Rain, whenever it occurs, is rarely a full-day event and often lasts for anything from 15 minutes to 2 hours and is somewhat predictable.  The rain is virtually perpendicular, which means you can cover yourself and stay dry (for a short while at least) with a newspaper. Sabah, also called ' land below the wind' by locals, because even though it's relatively near the Philippines, it is never affected by the extreme monsoons of the region. Many visitors do not weigh the so-called wet & dry season too heavily in their decision to visit Sabah, resulting in Sabah really enjoying an all year tourism season. Officially though, the wetter season runs from October to February and the dryer season from March to September. experience though is, in the dryer season, it might rain once a day and in the wetter season perhaps twice a day. But not every day.  The reason for the high rainfall recorded in the area is that when it rains, it rains hard.
  4. Sun Burn Risk
    The sun is always present, even when it's overcast, so stock up on a high-factor sun block. Buy ahead before going to the islands, as the islands charge a premium for a very small quantity. Be especially cautious when you go snorkeling, as the exceptionally interesting underwater life will distract your attention from the sun scorching your neck, back and legs (personal experience). Don't bother with a sun block less than SPF 20, but the lighter your skin, the higher you should use.
  5. What to wear
    Due to the climate people dress casually.  Locals will wear light material trousers with short-sleeved collared shirts, or t-shirts. Tourists, wearing shorts and t-shirts abound.  For business meetings, semi-formal wear is acceptable. Ties are rare and jackets extinct (save for the odd formal, evening function). Caution though, if you visit a Mosque or other religious places or sites, always wear closed shoes, long trousers and shirts with sleeves. Flip-flops, shorts, spaghetti strap tops and the like are considered disrespectful in these locations. Bring something warm, but light for the cooler evenings.  If you are going to attempt Mt. Kinabalu, bring warm trousers, a jacket and woolly socks and a beany will help. Also gloves, but not so much for heat as for the ropes you will hold on to on your ascent and decent (wool is a bad idea, the rough ropes will rip them up - again, personal experience). The usual swim wear is acceptable.  Topless tanning, and nudity in general, is illegal, but the odd topless tanner has been spotted on the islands. Beware though, in Asia in general, it is culturally offensive and you will be obviously gawked at by every local and other Asian visitor who pass you..

Visit http://www.kjc.gov.my/english/weather...  for a 7 day forecast for most major cities in Malaysia, including Kota Kinabalu.