Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Hangzhou to Guilin as you normally would.
The most flights from HGH to KWL are scheduled on a Monday (3 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (2 on average).
In terms of precipitation, rainfall in Guilin ranges from 1.6 - 15.4 inches per month. June is typically the wettest month, when rainfall can reach 15.4 in. January is typically the driest time to visit Guilin when rainfall is around 1.6 in.
If weather is an important factor for your trip to Guilin, 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 84.2 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 46.4 F).