What's the weather like in Tibet in March and April?

As far as my personal experience in Lhasa in recent years is concerned, March and April are the most uncomfortable seasons in Lhasa, with the least oxygen content and easy to get sick. In a year, sunshine is the worst (Lhasa is basically sunny all year round, but it will be cloudy and dusty in March and April). Then these two months are sensitive seasons, and the alert is strict. I suggest not to go to Lhasa at this time.