Thalassery experiences a severe summer and heavy monsoons; hence both these seasons are best avoided. The best time to visit the place is soon after monsoon till the end of winter (October to February). Those who want to get a glimpse of the festivities of Thalassery can plan a trip during Onam season (August to September).
Summers in Thalassery are hot and intense. Heat hits the town of Thalassery from the month of March and is continued till late May. The temperature during the season goes as high as 40°C. It is not advisable to visit Thalassery during this period. Those who plan to visit the town nevertheless are advised to carry cotton outfits.
Like any other town in Kerala, monsoon begins in Thalassery from June and is extended till September. Due to the proximity of coastal line, the town receives heavy rainfall. Visiting Thalassery during monsoon is not recommended as incessant showers will tamper with sightseeing.
Winter is the most pleasant and welcoming climate in Thalassery. December marks the beginning of winter and is continued till February. The temperatures during the season vary from 20°C to 32°C. It is an ideal time to visit the forts, plantations and other heritage buildings of the region.