This discussion is not very useful without people stating where they live and what the climate is like. Most years here in sunny northern California (except this year which is the coldest summer on record) I wear wool shorts with full length leg warmers from about November through April. After that it is too hot to wear anything but lycra shorts (except for this year).

Of course I'm only talking about long (20+ miles) rides. For anything else I just wear whatever I happen to be wearing (i.e. street or casual clothes).