Think you will find that the best groups are shot very early in the morning or very late in the evening on clear days. Wind has tendency to die down, no mirage, no clouds to play havoc with optical illusions on where target actually is as sun goes in an out etc
i know for super fast rounds in an m1a1 we use to lie to the computer and input 29.92 for barometric pressue.the pressure has alot to do with flight and speed and resistance.but finding the perfect day is tough so what the hell a good clear day no wind and a hundred miles from the nearest town
I'm with a lot of the "ole' timers", I shoot whenever I can and just make the most of it. I dont worry much about it if I'm shootin' groups at 100yds. Only if it's raining harder than a drizzle, or the outside temp. is approaching 100 degrees.
I think the conditions that are present when a light drizzle is occuring are almost perfect for shooting. When the temps get up there you have to fuss with the barrel. I shoot once or twice and take my rifle inside for 15-20 minutes. Not sure this is actually the best method (metal expansion) but keeps the barrel from getting too hot. I keep my test loads inside until I'm ready to shoot 'em.
If I'm going to be shooting farther than 100yds I will go on-line and get an accurate weather forecast with as much info as I can get and plug everything into JBM. Barometric pressure, temp., wind, humidity, actual velocity for that day, it all matters, I feel.
It helps that I have a range at home. This setup makes load development quick, in-depth and stress free (for me). I don't like doing load development at home and then having to drive to the range to test them out. I'm left hanging until I get back to the range. At home I can shoot all day long, varying components, seating depths (if needed) and clean my barrels as I go. Perfect setup for OCD people.
Shoot when you can, work when you have to. JohnnyK.