Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Vilnius to Cagliari as you normally would.
In terms of precipitation, rainfall in Cagliari ranges from 0.1 - 2.2 inches per month. February is typically the wettest month, when rainfall can reach 2.2 in. July is typically the driest time to visit Cagliari when rainfall is around 0.1 in.
If weather is an important factor for your trip to Cagliari, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 75.2 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 50.0 F).