Mumbai is never too hot or too cold because it is on the sea coast. The sea exercises a moderating influence on the climate of the shore. This is because sea water heats up and cools down less quickly than land. So in summer, the sea remains cooler than the land. As a result wind from the sea blows towards the land and cools it down. In winter, the sea remains warmer than the land. This raises the temperature of the land nearby.