If the forecast is looking grim, why not spend some time at Museum of History of Moscow? You'll be fascinated by just how many interesting facts you can uncover about the past here.
Situated in Moscow City Centre, this collection of historical artifacts is well worth a look. But you'll find plenty more to see and do in the area. Red Square, St. Basil's Cathedral, and Bolshoi Theatre are within close reach of Museum of History of Moscow.