I very rarely see them, raining or not.
But then the area I traverse mostly is the eastern area like from
Geylang, Ubi, Katong, Bedok, Tampines, Changi areas. Occasionally
to areas like Jurong and Yishun.
In one year I don't think I have more than 10 sightings. Five would
be nearer the number.
Do you see them? Often. Much less in the rain.