Thiruvananthapuram | Rain may play spoilsport during Keralam's key Onam celebrations this year, with the IMD forecasting heavy to very heavy showers in several districts on Uthradam and Thiruvonam days.

According to the district-wise rainfall forecast issued by the IMD Meteorological Centre here, heavy to very heavy rains are likely in several parts of the state on Monday, with isolated heavy rain also expected in many districts.

The forecast for August 25, Uthradam, the eve of Thiruvonam and one of the busiest days of the festival when people traditionally make last-minute purchases and preparations, shows the possibility of continued rainfall, though its intensity is expected to ease in several areas.

On August 26, Thiruvonam, the most important day of the Onam festival, light to moderate rain is likely across much of Keralam, with isolated heavy rain still possible in some districts.

The forecast could bring some uncertainty to outdoor Onam celebrations, shopping and family gatherings across the state, particularly in areas that receive heavy showers.

The IMD forecast shows a further improvement in weather conditions from August 27, with no rainfall warning indicated for the state on August 27 and 28.

Keralam is celebrating Onam with a week-long programme of cultural events and festivities, but the monsoon could add an unpredictable element to the celebrations, especially on Uthradam and Thiruvonam.

The weather office has also advised people to remain cautious during thunderstorms and lightning and strong surface winds associated with the rain.