What part of Yemen, and what time of year? The winters(dry season) are cold and dry, relatively speaking. The wet season is when they are booming.
This “wet” season is relative as well, with average days , Idd to Yarim region, around 40% to 50% humidity.
The night is what maters. It is cold even down to 50 degrees on average and 100% humidity . This is where they get their humidity.