This how to change the weather in the snow resort. You can find it on a balloon. Do this while the game is loading before before you enter the snow resort.

Code	Effect
Hold C, Z on nunchuk and LEFT on the direction pad	Cloudy weather.
Hold C, Z on nunchuk and Down on the direction pad	Stormy weather.
Hold C, Z on nunchuk and UP on the direction pad	Sunny weather.