Madurai, Tiruchirapalli and in some places in southern districts are experiencing rains which in turn has slowed down the voting.
There were also reports of malfunctioning of voting machines in some places.
In Chennai, voting is progressing at a brisk pace.
DMK chief M.Karunanidhi and the state leader of BJP Tamilisai Soundararajan have cast their votes.
Actors like Rajinikanth, Ajith also cast their ballots.
Polling in the 232 out of 234 assembly constituencies began in Tamil Nadu on Monday morning.
Around 5.82 crore voters are set to elect a new 234-member assembly in the polls being held on Monday and on May 23 for Thanjavur and Aravakurichi constituencies.
The Election Commission has postponed the elections in Thanjavur and Aravakurichi after it received complaints about large scale distribution of money to the voters by political parties and their candidates vitiating the electoral process.
In the 232 constituencies, there are 3,728 candidates in the fray.
In 234 constituencies, a total of 3,776 candidates including 320 women are in the fray. There are 1,566 independent candidates are also trying their electoral fortunes.
The state is seeing a multi-cornered contest.
The ruling AIADMK is going to the polls aligning with a couple of smaller parties fielding its candidates in 227 seats and the balance seven has been given to its allies.
The DMK has aligned with the Congress, two Muslim parties and some smaller outfits.
The third front led by the DMDK comprises the CPI-M, CPI, VCK, TMC and MDMK under its fold.
The PMK is contesting alone while the BJP has aligned with few smaller parties.