That's what I do too, but if you can't control your fermentation temps then picking a yeast based on the prevailing conditions makes sense.I usually pick my yeast based on the temperatures in my house. I usually go through the list of yeasts from the northern brewer website, my local brew shop, or the wyeast site and pick according to the temperature tolerance and the characteristics I'm going for. It's hard to get too warm for Wyeast 3724, Belgian Saison.
I do the opposite. I base yeast choice on the flavor profile I want in the beer, then adjust the fermentation environment accordingly.