WASHINGTON — The Washington Monument reopened at 9 a.m. Monday after having been closed all day Sunday and part of Saturday night.

The monument suffered two elevator outages in less than 12 hours — at about 9:20 p.m. on Saturday, and again shortly after the opening on Sunday.

National Park Service spokesman Mike Litterst said the monument would reopen Monday morning, adding that the outages were due to “a tripped breaker caused by a voltage drop of incoming power to the monument.” On Sunday he said the extreme heat that has battered the region played a part in the outage.

It’s at least the fourth elevator outage at the monument this year.