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 similar to Lviv. You can assume this to be the case over the next 3 days.
Our data indicates that the weather will be 36 °C on average in the month of April. The temperature in Lviv is typically colder than in Bangkok Intl. If you're traveling when the temperature is at its warmest, push to plan early, as flight price and availability will have an impact on your travels. For the best results, search for flights well in advance or after peak season.