Heavy to very heavy rainfall occurred at various parts of Alapuzha district with Mavelikkara recording 13 cm, while Alapuzha, Haripad and Kayamkulam recorded 9 cm rainfall, Indian Meteorological Department (IMD) Director, S Sudevan, said in Thiruvananthapuram.
Vadakara (Kozhikode) and Koni (Pathnamthitta) recorded 7 cm of rains, he said.
"However the rains have been comparatively less in the hilly areas of the state," Sudevan said.
Neyyatinkara and Varkala in Thiruvananthapuram district also received heavy rains.
Very heavy rainfall is likely to occur at one or two places in Kerala on Wednesday, an IMD bulletin said.
Strong winds from the westerly direction with speed occasionally reaching 45-55 kmph is likely to hit Kerala and Lakshadweep coasts in the next 24 hours commencing from 2 pm, it said.
IMD had earlier in the day said that the southwest monsoon hit Kerala and the northeast, two days ahead of the scheduled arrival of the crucial seasonal rainfall.
Cyclone Mora, which hit the Bangladesh coast on Tuesday, aided the advance of the monsoon, director general of the India Meteorological Department K J Ramesh said.
The normal onset date for the monsoon in Kerala, which marks its official arrival in the country, is June 1.
Last year, the monsoon hit Kerala on June 8, seven days after its scheduled onset date.
Image for representation only.