Silver Lake is good in the spring and fall facing south west. Pretty much any wind direction with a southerly component is good. Early and late season you can launch from anywhere on the huge grassy beach area. During the summer when the swim buoys are up you have to launch to the right (west) of the beach but it's still good.
On a good day there can be 10-20 sailors out. Watch out for a water obsticle when you get down by the reeds to the far west of the launch. There is a rock that sticks up just above the water. Defenitely NOT something you want to hit and or land on....and it comes up quick. The best thing to do is stay away from that area.
There are bathrooms/changing area which is nice and hiking trails if a non-windsurf partner comes along.