The IMD has forecast heavy rain, strong winds in Chennai and five other Tamil Nadu districts today due to an upper-air trough. The districts likely to be affected include Chennai, Tiruvallur, Kanchipuram, Chengalpattu, Tiruvannamalai, and Ranipet. Fishermen have been warned not to venture into the sea until June 30 as winds of up to 60 kmph are expected.