Well I think I can probably chime in, since I live in Palmdale. lol
The general consensus about it being windy is generally correct, living here and not riding in the wind would be like living in Seatle and not riding in the rain.
Generally in the Summer months we are between 90 and 105 degrees during the hottest part of the day, but there is very little humidity and it is still pretty comfortable to ride as long as you keep hydrated.
The winters are no where near as cold as some places, with daily lows rarely below freezing and nights rarely dropping below mid twenties. The killer however is the wind which tends to cut through you.
In the actual city of Palmdale the riding is very flat as was mentioned but it is easy to get to canyons and mountains either by adding mileage to your ride or by simply driving 20-40 minutes outside of town.
We do have one cycling club up here in the area
www.highdesertcyclists.com the whole group is made up of fairly good guys and gals with only a few snobs. We have weekly rides on both Saturday and Sunday mornings that go anywhere from 25-50 miles and also they do a few longer events each year.
The roads in town are okay for cycling, I haven't had or heard about too many road rage incidents, but for better cycling head to the west of town and the roads are fairly trafic free and nice.
Elizabeth lake road has some rolling hills and goes through some dairy farm country and also gives access to all of the different canyons which you can ride from here as well.
We aren't the cycling meca that a place like Solvang would be but overall it isn't so bad, plus we are close enough to where you can hit all the really good rides without too much trouble.