It is amazing what you can do in the Grand Canyon when the weather is bad!! 

 You can go to the Kolb studio and see some amazing art work.

 Visit the Hopi house and see some amazing native american crafts.

Have a great meal at the El Tovar.

 Visit the History Room at the Bright Angel Lodge.

Go to the Look-out Studio and get a glimpse of the Canyon (maybe).

Have a cocktail in the El Tovar lounge.

Ride the shuttle to Hermit's rest and see the fireplace where our current  president  had his picture taken.