A forecast ability may be activated only during the upkeep step of the card’s owner and only once each turn. The controller of the forecast ability reveals the card with that ability from their hand as the ability is activated. That player plays with that card revealed in their hand until it leaves the player’s hand or until a step or phase that isn’t an upkeep step begins, whichever comes first.
July 17, 2015 · Magic Origins
If a permanent has multiple instances of graft, each one works separately.
July 13, 2013 · Magic 2014
If a creature has multiple instances of graft, each one works separately.
June 17, 2011 · Commander 2011
rule 702.57b not present in this release
February 1, 2010 · Worldwake
If a spell has multiple instances of ripple, each triggers separately.