Over on gundigest.com, Dave Morelli has an article in which he advocates gun training in bad weather.
I see nothing in the article with which I disagree. The author isn't advocating going out in crappy weather to learn the fundamentals. He's telling you to get out there in sub-optimal conditions to learn what your gun does -- and what you do -- when it's windy, rainy, or cold.
Based on my own experience in shooting practical rifle matches at my club, operating your gun in extreme weather conditions stresses the shooter in ways not experienced when it's 75 and sunny. If it's humid, lenses (both eye glasses and scope lenses when you accidentally breathe on them) get fogged. If it's snowing ice can form on your gun while you're waiting to shoot, rendering it slippery. When it's hot, your sweat gets in your eyes and on the gun.
Or step in a 10" deep puddle of ice water while your waterproof boots are only 8" high, then go on to finish the stage.
In cold weather your clothing limits your movement and makes working fine controls more difficult.
Get the basics down in good weather. Then go see what happens when it's shitty out.
It was about 12 degrees out when this pic of me was taken back in January.
Under stress you will default to the level of your training. If you train easy, you will fail get life gets hard.