A bit of clouds and wind are good things, but I had two new guys out in my boat a week ago and it was hot, calm and flat. And litterally as I was telling them that these conditions are tough and that we shouldn't hold our breath, I hooked (and subsquently lost boatside) a 50" fish. And one guy had a high 40 follow later that day when it was even hotter, sunnier and calmer. Went out on Friday in the wind and clouds for 9 hrs and didn't even get a follow from six different places. Get out whenever you can.