Good question Derek....
I have a two-part answer on this one.... part one goes something like this: I believe that there are definitely conditions which favour the type of angling I do, which tends to be mostly bait-fishing for fish like chub, carp, tench, roach, bream, barbel... so given the choice, I would like less light - overcast rather than sunny, and without it raining then the darker the better. Also, in terms of temperature, I'd like a warmer than usual winter day, or a cooler than usual summer day. That's what I want given the choice...
Part two of the answer goes like this: I can't just drop everything else in my life and go fishing when I please because the conditions look good. With work and family commitments, if a man like myself wants to spend a whole day (or even better, a weekend!) fishing then he needs a pretty long run up! So for example, I'm currently looking at planning a long weekend in October (either on the wye or severn) which I will likely commit to a date for in about three weeks time. So when that date comes around, I will go fishing regardless of what the weather's doing, because that's how it has to be. And then - I will cut my cloth in terms of the techniques I use according to the conditions I find. That may sound like the tail is wagging the dog, but like I say it's just what happens.
(all of that said, at this time of year it's a lot easier to grab a couple of hours in the evening as and when I can, but it usually involves taking one of the kids with me and then it's not quite the same as going by yourself. Not that I'd change it for the world!!!)