After practicing the weather with the chant and introducing the 'let's play' with the watch and think you can use this game to practice the two expressions together. (Page 6 and 7)
I'd recommend going over the vocabulary pretty well before starting. We did card exchange for the weather as well as what's missing. We did 'what's missing' and match weather to 'let's' with the 'lets play vocab'.
For this game. The students make groups. Give the groups a bit of time to pick a weather from the weather column and a Let's from the let's column. They should practice a little and then when ready they can raise their hands. If all members have raised their hands the teacher calls that group. They speak their sentences together. For example 'It's sunny, let's make a snowman'. The teacher clicks on that square on the grid and on the board reward the group with those points. Then they sit down and another group has a chance. Once every group has had a chance go for a second round letting each group try again. After every group has had two chances total the points and clap for the winners.
It takes about 10 minutes for each group to go twice. There are three screens if you want to keep the game going or want to play it again the next week as a review.
I'd recommend against using it in very large classes. If there are more than six groups the waiting time would be too long.
I've included the weather cards I use as practice, the small cards I use for card exchange and the 'Let's play' cards for practice as well as the powerpoint game.