When it rains one generally avoids going out but may decide to go out if the weather clears up. The idiom to make (or take) a rain check means to decline an offer but be willing to consider it for later or accept it later.
1. When John got a call from his boss, he decided to call his girlfriend and take a rain check for their movie plans.
2. On getting a blast of chilly air when he stepped outside the hotel, Bertram took a rain check on his ski outing.
3. Mrs. Prabhakar was bitter about the fact that her husband always postponed their trip to Ooty and found some excuse or the other to take a rain check.