The Monument Valley Mitten Shadow happens twice each year, first in late March peaking around the 30th, then again in September peaking around the 13th. On these days, and for a day or two before and after, West Mitten Butte casts a perfect shadow upon East Mitten Butte at sunset creating what’s come to be known as the ‘Monument Valley Mitten Shadow’. Adding to the short window that the shadow is visible each year, is the fact that the sky must be clear enough for direct sunlight to be hitting the mittens. If it’s overcast at sunset, the shadow doesn’t happen, so plan accordingly if you’re traveling to the area specifically to witness this event!