All deserts have high daytime temperatures.

No, some deserts are cold deserts and the temperature can be bitterly cold the year round. An example is Antarctica which remains quite cold, even in summer. The Patagonian Desert of Argentina has cool or cold temperatures all year, also. The Atacama Desert rarely gets warmer than 80 degrees F.

No some or cold but most are hot 

It's lithogenous i believe of course i looked it up.