As you know, Brunei has a tropical climat. Temperature is fairly constant, averaging between 23-33 C degrees all year round.
The climate is monsoonal, and normally there is supposed to be a wet season between November and February, when there is higher and more constant rainfall.
However, this year, it seems to have come slightly later - since we've been back, we have only had ONE clear afternoon. The rest of the time (for over a week now) it has rained constantly.
It's also been pretty cool. Yesterday driving in to town in the late afternoon, I experienced the lowest temperature since we've been here: 21 degrees. Pretty cold!