Thrissur Pooram: Thrissur Pooram is one of the most popular and grandest temple festivals celebrated in Thrissur. It is a 36-hour-long festival that takes place in the Malayalam month of Medam (April-May) at the Vadakkunnathan Temple in Thrissur. 

Thrissur Pooram is a festival that is celebrated with great enthusiasm and devotion by people from all over Kerala. It is known for its spectacular display of caparisoned elephants, traditional percussion music, and fireworks. The festival is a grand spectacle that attracts tourists and devotees from all over the world. 

The festival is marked by a grand procession of elephants adorned with colorful umbrellas, gold-plated caparisons, and bells. The procession begins from the Thiruvambadi Sri Krishna Temple and Paramekkavu Devi Temple and culminates at the Vadakkunnathan Temple. The highlight of the festival is the display of fireworks that takes place in the early hours of the morning. 

Thrissur Pooram is also known for its traditional percussion music, which includes the Chenda, Ilathalam, and Kombu. The festival is a celebration of the rich cultural heritage of Kerala and is a testimony to the unity and harmony that exists among people of different religions and castes in the state. 

Navarathri: The festival typically lasts for nine days and is dedicated to the worship of the Hindu goddess Durga and her various forms. 

In Thrissur, Navarathri is celebrated with great fervor and enthusiasm. The city is known for its spectacular Navarathri celebrations, which feature a variety of cultural programs, musical concerts, and traditional dance performances. The main highlight of the festival is the elaborate display of dolls and figurines, known as 'golu' or 'kolu' in Tamil, which are arranged on steps or platforms. 

During Navarathri, people visit each other's homes to see the golu displays and exchange sweets and gifts. Special pujas are also performed in temples and homes to invoke the blessings of the goddess. 

In Thrissur, one of the most popular events during Navarathri is the 'Vijayadashami' procession, which marks the end of the festival. The procession features an elaborate display of decorated elephants, traditional drummers, and other cultural performances, and culminates in the immersion of the idols of the goddess in a nearby river or lake. 

Vishu: Vishu is a major festival celebrated in the southern Indian state of Kerala, typically on April 14th every year. 

During Vishu, people in Thrissur decorate their homes with flowers, light lamps, and prepare special dishes. One of the main rituals of the festival is the Vishukkani, which is a traditional arrangement of items like rice, fruits, flowers, and coins, placed in front of a mirror to signify abundance and prosperity in the coming year. 

Another important aspect of Vishu in Thrissur is the cultural programs and events that are organized in the city. Various art forms like Kathakali, Mohiniyattam, and Ottamthullal are performed by professional artists and local troupes, showcasing the rich cultural heritage of Kerala. 

The Thrissur Pooram, which usually falls around the same time as Vishu, is another major festival celebrated in the city. It is a grand festival that involves the display of decorated elephants, traditional percussion music, and fireworks.

Arattupuzha Pooram: The festival usually takes place in March/April and lasts for seven days. 

The main attraction of the festival is the grand procession of more than 60 decorated elephants accompanied by traditional percussion instruments like Chenda, Thimila, and Maddalam. The elephants are adorned with colorful umbrellas, peacock feathers, and bells, and are led by skilled mahouts. 

The festival begins with the flag hoisting ceremony at the Sree Sastha Temple in Arattupuzha. During the festival, various cultural programs like Kathakali, Chakyar Koothu, and Ottamthullal are performed by artists. The traditional percussion ensembles like Panchavadyam and Pandimelam are also an important part of the festival. 

The climax of the festival is the Arattupuzha Pooram procession, which takes place on the final day. The elephants from various neighboring temples are brought to the Sree Sastha Temple, and a grand elephant procession is taken out. The elephants line up face-to-face, and the spectators witness a breathtaking display of fireworks.