"Their Royal Highnesses have appreciated all of the support they have received from people around the world since their wedding," the palace said.
Merkel's allies slumped to their worst election results in decades. Big winners were the environmentalist Greens and far-right Alternative for Germany.
"If I had not made that speech, we would not have won," the president says in a TV interview.
Some of the wildfires that engulfed California a year ago were caused by downed power lines and damaged electrical equipment.
Some analysts said it was difficult to imagine Saudi Arabia taking action that would hit world oil supply.