Well not every day. But yeah; that's the general idea
In Singapore though; the storms/thunderstorms are still very "local." They only cover a small area. It can be raining profusely in one area and bone dry 10 minutes walk away. Of course said thunderstorm then has already completely stopped by the time you reach that bone dry area too. And by the time you reach your original location, it is already completely bone dry again.
What could happen, and I believe has happened for the last two or 3 years; is that during the Grand Prix, which was forecasted for thunderstorms, the showers happened in other areas of the city; so while the forecasts were accurate, they weren't in the location talked about.
Speaking of locations; how come the DRS zone hasn't been announced yet?