What is the origin of the phrase "rain check"?

Can you possibly tell me the origin of the word rain check? Not only is it possible - it is probable!

American baseball fans will be familiar with the term, as that is where it arose: when a game was rained out, those who had tickets for that game were given a rain check which they could redeem at another game. That might explain why efforts to prevent a baseball game from being canceled by rain (and rain checks issued) are so prodigious: covering the playing field with tarp, keeping the fans and players waiting as long as possible to see if the downpour will end. The term was soon used metaphorically, and by the 1970s it had spread outside the U.S. and into other English-speaking countries. The use of the term as early as 1884 gives some indication as to the popularity of baseball in the U.S. even at that time: 'The heavy rain yesterday threw a damper over local operations. At each of the parks the audience had to be content with three innings and rain checks.' (St. Louis Missouri Post-Dispatch 26 May).

http://www.takeourword.com/TOW143half/page2.html

Back in the days before baseball stadiums had roofs, tickets to baseball games had a counterfoil entitling the bearer to see another game if the one for which the ticket was purchased was cancelled because of rain. That counterfoil, or receipt, was a rain check.

This term comes from baseball, where in the 1880s it became the practice to offer paying spectators a rain check entitling them to future admission for a game that was postponed or ended early owing to bad weather. By the early 1900s the term was transferred to tickets for other kinds of entertainment, and later to a coupon entitling a customer to buy, at a later date and at the same price, a sale item temporarily out of stock.

http://www.answers.com/topic/rain-check

Finally, it makes sense. Over here, that's spelled "cheque" so I always thought it was check as in "check to see if it's raining".

Actually, a rain check has a couple of meanings. I believe it originally came from baseball. It was when a customer was given a new ticket for the make-up game if a baseball game is started but does not reach the point of becoming official (5 complete innings). This idea is generally credited to Charles Ebbets.

As noted below it is also something retailers do for customers when the merchant runs out of an advertised item. The merchant will give the customer a rain check to buy the out of stock item when it is back in stock.

Another use of the term rain check is when people decline an invitation. If someone asks you to go out for drinks and you either can't go or don't want to go you might politely ask them for a rain check suggesting you'll do it at a later time.

http://www.dictionary.com/browse/rain-check