The Department of Meteorology says that showers or thundershowers will occur at times in the Uva province and in Batticaloa, Ampara, Polonnaruwa and Hambantota districts.
Showers or thundershowers will occur at several places elsewhere except Northern Province, particularly after 2.00pm.
Heavy falls (about 100 mm) can be expected at some places in Western and Sabaragamuwa provinces and in Galle, Batticaloa and Ampara districts, it said.
Meanwhile showers or thundershowers are expected to occur at times in the deep and shallow sea areas off the coast extending from Trincomalee to Hambantota via Batticaloa and also from Galle to Puttalam via Colombo.
Showers or thundershowers will occur at a several places in the sea areas off the coast extending from Galle to Hambantota in the evening or night.
Winds will be north-easterly in direction in the sea areas and wind speed will be 30-40 kmph.
Sea areas off the coast extending from Mannar to Colombo via Puttalam and also from Matara to Potuvil via Hambantota will be fairly rough at times as wind speed increase up to 50 kmph at times.
Temporarily very strong gusty winds (up to 70-80 kmph) and very rough seas can be expected during thundershowers, the Met Department said.