It's often used when someone makes an incorrect prediction about an outcome or future event. He missed his guess thinking it would rain today; the weather is clear.
Pro Tip 2/3
Not about Aim
'Miss your guess’ is not about physical aim, it's about being wrong in decision or opinion. You'd miss your guess if you assume all cats hate water; some actually enjoy it!
Pro Tip 3/3
Casual Conversations
This phrase is more common in casual speech rather than formal writing or advanced discussions. If you miss your guess on the trivia question, we'll lose the game.