What do you think the PokeSpe characters do on a snowy day?
SPOILER
It is a coincidence that you mention this since it is snowing in the Pokemon Special canon in Sinnoh. Maybe the writer will tell us how the characters fells about snow.
End of SPOILER
Red: Will battle in the snow.
Green: I am not sure he might either say inside the gym and have a snow related even take place with Pokemon involved.
Blue: I can see heading up a icestaking constant and make profit off of it. She might start to icestake herself after observing other people.
Yellow: She will probably build a snowman or snowwoman and decorate it.
Gold: He would probably be snowboarding and also try to flirt with girls like everyone else said.
Silver: He will probably do nothing I guess.
Crystal: She will probably train herself or her Pokemon to endure the snow.
Ruby: He was probably stay inside the house and decorating his house.
Sapphire: I can really see her playing in the snow and throwing snowballs.
Emerald: He will probably build a igloo and use it as a defense against heightist people.
Diamond: I can see him baking cake, cookie, and other treats and making hot chocolate with marshmallows and eating and drinking it all up along with his Pokemon.
Pearl: I do not know how Pearl will react to snow. He also might be on a stage doing comedy jokes that has something to do with snow along with Diamond.
Platina: It would not surpise me if she went out in the snow considering that she has been to
SPOILER Snowpoint City and has try skiing and she might become better at it, who knows.
End of SPOILER