ST. LOUIS — The Arch will be dark starting tonight through November, 17, 2023. The National Park Service is installing a new lighting system to reduce the overall energy needed to light the monument by 60%.

The new LED lights will replace the 26 static Xeon skylights installed in 2018. They only use 1200 watts per unit compared to the 7000 watts required by the current lighting system.

There are benefits besides power efficiency with the new lighting system. It is more accurate in controlling focus and color temperature. This will make the monument brighter at night and reduce stray light for migratory birds in the night sky.

The money to install the new system is coming from the Gateway Foundation.

The lights were off in September to protect birds migrating south for the winter. The monument does this twice annually to protect 40 percent of the nation’s migratory waterfowl who use the Mississippi River corridor during their spring and fall migrations.