Called "the pigeon orchid'. You can see great masses of it in Singapore, growing at the sides of the roads . The big temperature drop is caused by thunderstorms. So when you see the lightning flashes, start counting - not 1-2-3-4 (seconds) to wait for the thunder , but 1-9 or 10 (days ) to wait for the mass flowering. Quite stunning if you manage to catch it.
Unfortunately I have never been there for longer than a week at a time, but my wife taught school there in the days when it was a British colony - long, long ago, and she remembers this.