Maximum temperatures are likely to reach around 40°C in isolated places in Palakkad district on Saturday and Sunday, according to the India Meteorological Department.

Temperatures may rise to 39°C in Kollam, 38°C in Thrissur and Kottayam, and 37°C in Pathanamthitta, Alappuzha, Ernakulam, Malappuram, Kannur, Kasaragod and Kozhikode districts. Thiruvananthapuram is expected to record around 36°C. These levels are 3 to 4 degrees Celsius above normal.

The department also said maximum temperatures were 'very likely' to exceed the 98th percentile of climatological values at a few places across Kerala till April 26.

Hot and humid weather conditions are expected to prevail across these districts, except in hilly areas, during the same period due to high temperature and humidity. 

Meanwhile, the Kerala State Disaster Management Authority (KSDMA) has warned that a high ultraviolet (UV) index has been recorded in the state over the past 24 hours. Continuous exposure to UV rays can cause sunburn, skin diseases, eye problems and other health issues.

The highest UV exposure is typically recorded between 10 am and 3 pm, and the public has been advised to avoid prolonged direct sunlight during these hours.

KSDMA said people working outdoors, including fishermen engaged in sea and inland fishing, those involved in water transport, bikers and tourists, should exercise caution. Individuals with skin diseases, albinism, eye conditions, cancer patients and other immunocompromised groups have been asked to be particularly careful.

People have been advised to wear protective gear such as hats, umbrellas and sunglasses while going out during the day, and to opt for cotton clothing that covers the entire body. Taking rest breaks in shaded areas during travel is also recommended.

Authorities noted that UV levels are generally higher in tropical regions and at high altitudes. Even on clear, cloudless days, UV radiation can remain high. Surfaces such as water and sand can reflect ultraviolet rays, increasing exposure levels in such areas.

Earlier, authorities had warned that the prevailing weather conditions pose health risks, particularly for vulnerable groups such as infants, the elderly, people with chronic illnesses, and those exposed to direct sunlight for long periods or engaged in heavy work. 

Pregnant workers and those with medical conditions should be given additional attention, and workers have been cautioned to avoid direct sunlight between 11 am and 3 pm.

Authorities also advised keeping cattle indoors during peak heat hours and warned against leaving children or pets inside parked vehicles.