Maximum temperatures are likely to touch around 40°C in Palakkad, 39°C in Kollam, and 38°C in Pathanamthitta, Thrissur, Kozhikode and Kasaragod on Sunday, according to the India Meteorological Department. Temperatures may reach 37°C in Kottayam, Ernakulam, Malappuram and Kannur, and 36°C in Alappuzha and Thiruvananthapuram — about 3–4°C above normal, the weather agency said. 

In several places, temperatures are expected to cross the 98th percentile of climatological values, indicating unusually high heat levels. Hot and humid conditions are likely across most districts, except hilly areas.

This weather can pose serious health risks, especially for infants, the elderly, people with chronic illnesses, and those exposed to direct sunlight or doing heavy work. Heat-related issues such as heat cramps and heat rash are likely during peak hours (11 am to 3 pm). 

The Idukki District Collector has issued a high alert after the Kerala State Disaster Management Authority (KSDMA) flagged a UV index of 8 in Munnar. The Collector has directed that plantation workers should not work during peak hours, and authorities will ensure that estate owners comply with this directive. Tourists and residents in the area have also been warned to take necessary precautions.

Additionally, the KSDMA has issued an alert for thunderstorms, with light rainfall and gusty winds reaching up to 40 kmph likely at one or two places in Pathanamthitta, Kottayam and Idukki.

Precautions to follow:

• Avoid prolonged exposure to heat
• Wear lightweight, light-coloured, loose cotton clothing
• Cover your head with a cloth, hat or umbrella when outdoors
• Drink plenty of water, even if not thirsty
• Schedule strenuous work during cooler parts of the day
• Increase the frequency and duration of rest breaks for outdoor work
• Give extra care to pregnant workers and those with medical conditions
• Avoid direct sunlight between 11 am and 3 pm
• Keep cattle indoors during peak heat hours
• Do not leave children or pets inside parked vehicles
• Monitor rallies and public gatherings during peak heat hours
• Stay cautious as high heat and humidity continue across the state.