I have Anna’s hummingbirds that over winter, at the same latitude as Williston or Minot ND, though I am on the coast.
The Pacific Ocean does have a tempering effect on the weather.
I find it interesting that your hummers migrate.
Many do stay here...this is a major flyway for many birds migrating across the gulf.
A major bird-watching area. We have an Audubon Society Center just down the street on Dauphin Island.
"Dauphin Island , Alabama is one of the top birding spots in the Southeast and is recognized as a Globally Important Bird Area by the National Audubon Society and BirdLife International. An incredible 350 species have been reported on the island. Spring migration is the first landfall for many Neotropical birds who make the 600-mile flight across the Gulf of Mexico from the Yucatan Peninsula. Under adverse weather conditions, large flocks of exhausted birds of many species may seek shelter on the Island in a truly spectacular "fall-out".
'Fall-out' is a real phenomena here. Exhausted birds arriving from the south will see land and just quit flying, literally falling out of the sky.
I was on subs and some times when we would surface, birds lost at sea would crash onto our decks in a similar fashion.