Climate is a compound sign. First, sign weather, then sign tendency. To sign weather, form both hands into the ASL letter W sign as you make them face each other in front of you. Then shimmy your 'W' hands down a few inches in alternating directions, followed by making the 'tendency' sign with your dominant hand.
To sign tendency, hold your dominant hand wide open, extend the middle finger forward, then flick it forward from your dominant shoulder.
Teach your toddler the climate sign when you begin to introduce the different seasons to them, or when they become inquisitive about the different weather patterns they've noticed in the passing of months.
This is a useful flash card taught best in conjunction with the other flash cards pertaining to the weather elements, temperatures, seasons, and the colors represented by them.