Hottest October day ever: Record breaking temperatures soar from Midwest to the South

Dangerous, record-breaking heat is taking over the South and Midwest.

In Ohio, all classes and after-school activities at Columbus City Schools were canceled Tuesday due to the heat.

These cities not only broke daily records, but broke the record for hottest October day:
-- New Orleans: 95 degrees
-- Nashville: 98 degrees
-- Indianapolis: 92 degrees
-- Huntington, West Virginia: 95 degrees
-- Pensacola, Florida: 96 degrees
-- Mobile, Alabama: 96 degrees

But at the same time, the West felt like winter on Tuesday: temperatures reached 37 degrees in Billings, Montana, and 47 degrees in Idaho Falls.

The record heat will move to the East Coast on Wednesday, with temperatures possibly reaching 90 degrees in New York City and 95 degrees in Washington, D.C.

Meanwhile, residents from New Mexico to Michigan are under flood alerts. Some cities, already drenched, could see more than 4 inches of additional rain through Thursday.

Near Duluth, Minnesota, some roads were already submerged under water as heavy rain fell and rivers neared record flood stage.

ABC News' Will Gretsky contributed to this report.