The India Meteorological Department (IMD) has issued a heatwave warning for Mumbai, Thane, Raigad, and Palghar starting Friday. Daytime temperatures are expected to exceed 38 degrees Celsius in Thane and reach 36 degrees Celsius in Mumbai. This warning follows a recent yellow alert issued for the region, where temperatures approached 40 degrees Celsius last week. Although Mumbai experienced a brief respite with temperatures dropping to 34 degrees Celsius, the heat is set to return. The IMD has advised outdoor workers to avoid direct sun exposure during peak hours and to schedule strenuous activities for cooler times of the day. The region has already seen an early onset of heatwaves this year, with six such days recorded in March. Following the heatwave, light rain and thunderstorms are anticipated in Thane from May 18 onward, while Mumbai is expected to remain dry with clear skies.