An intense spell of thunderstorm came down on the city on Sunday morning.

Accompanied by a series of lightning and rumblings of thunder, the rain started around 9.30am.

The rain was not uniform. Cossipore received around 42mm of rain, Behala got 37mm and Patuli and Dum Dum, 20mm each.

The rain was not uniform because the southwest monsoon currents are weak in south Bengal, as they are across most of the Indian heartland this week, said Met officials.