When travelling, it's generally smart to pack in preparation for rain or any other conditions that may arise. The rainfall in Bangkok Intl is roughly greater than that of Mangalore. You can assume this to be the case over the next 3 days.
Some of our airline partners flying from Bangkok Suvarnabhumi to Mangalore Bajpe have new flexible policies in place due to COVID-19. IndiGo is one of the carriers where you may find flexible change policies. You can use our site to filter for airlines like IndiGo with this kind of flexibility.
We forecast the temperature to be around the 36 °Cs in April, on average. The temperature in Mangalore is generally colder than in Bangkok Intl. Book flights in a timely manner in correlation to your departure date.