Do you mean this:

Perhaps they’ll also help with the Singaporean phenomenon of the seeming complete disappearance of taxis when it rains—an almost daily occurrence in the tropical clime.

My question is whether the disappearance is real, or just perceived, as when it starts to rain, the available taxis are flagged to use immediately.

I'm pretty sure it's the latter - when it rains, people take all the taxis. This is what Singaporeans say, and locals in nearby Kuala Lumpur have said the same.

Click "phenomenon"

Thanks, I didn't spot that.

Looks like the pay structure (and possibly taxi pricing regulation) is silly for drivers.