Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Kempegowda Intl to St Anton as you normally would.
In Bangalore, there will be less rainfall in Bangalore compared to Innsbruck over the next 3 days.
Expect the weather to be around 34 °C on average in April. As the temperature peaks, try to get your plans done early, as flight price and availability will have an impact on your travels. The climate in Innsbruck is generally colder than in Bangalore.