Yup, it is, and it has happened. Singapore is such a hot country all year round with almost no farmland in existence, so in all humbleness the more rain the better.
Places outside wouldn't be so crowded too. Also floods in Singapore are really nothing than compared to those in other countries, including even Malaysia. Nobody dies here and help is always within reach so people should be thankful and not make too much of a fuss out of it.