Kerala is known for its vibrant and colorful Hindu festivals, which are celebrated with great enthusiasm and joy throughout the year. Here are some of the major Hindu festivals celebrated in Kerala:

Onam: Onam is the most important festival in Kerala, which is celebrated in the month of August-September every year. It is a harvest festival that marks the homecoming of King Mahabali, who is believed to visit Kerala during this time. The festival is celebrated with flower decorations, traditional dance forms like Thiruvathira Kali and Onam Sadya, a grand feast that includes 26 dishes.
Vishu: Vishu is the Malayalam New Year, which is celebrated in the month of April. On this day, people wake up early in the morning to see the Vishukkani, a set of auspicious items including rice, fruits, and flowers arranged in a pot. The day is also marked by fireworks, traditional food and family gatherings.
Thiruvathira: Thiruvathira is a festival celebrated by women in Kerala, which is held in the month of December-January. It is a celebration of the birth of Lord Shiva and is marked by traditional dance forms like Thiruvathira Kali, which is performed by women in a circle around a lighted lamp.
Navaratri: Navaratri is a nine-day festival celebrated in honor of Goddess Durga, which is celebrated in the month of October. It is a time for fasting and prayer, and is marked by traditional dance forms like Garba and Dandiya.
Diwali: Diwali is the festival of lights, which is celebrated in the month of October-November. It is a time for family gatherings, lighting of diyas and lamps, and the exchange of gifts.

These are just a few of the many Hindu festivals celebrated in Kerala. Each festival has its own unique traditions, customs and significance, making Kerala a vibrant and diverse state when it comes to festivals.