Mig Gred
Hiya Mig!
You're definitely right that Earth deserts are a land of total extremes and most are renowned for having blisteringly hot days and chilling nights, but there are a few things to point out here.
For one: This is a space planet, and there's a very real possibility that there are two suns orbiting it which could contribute to the desert landscape. As such, it may not be particularly cold at any given time. Of course, that's just speculation, because very little is officially written about the world or the solar system.
For two: The Draelvasier, like many intelligent races, do wear clothing, so it shouldn't prove to be too terrible a hindrance. After all: people can walk through deserts too for a while.
Most importantly though is that during the official SJO Dominion of the world, the rough temperature of the planet was remarked as "a pleasant spring day"
Epicenter: SJO Dominion of Sev Tok The world of Sev Tok was used to ground-quakes. On a pleasant spring day, the world began to tremble. The inhabitants of Sev Tok braced, much like they had done on several occasions. The rumbling grew stronger, the people hunkered down to wait it out... but...
www.starwarsrp.net
So - presumably, while real-world deserts are terrible, Sev Tok is just low on moisture, but otherwise fairly amicable temperature-wise.