As a deep freeze grips parts of America in a typically slow season for housing, first-time buyers are flocking to Redfin Corp.’s property tours and classes, signaling their renewed interest in the market.

“We are really hitting records in early-stage demand, in terms of people going on tours or even writing offers,” said Nela Richardson, the chief economist at Seattle-based Redfin, which has real estate offices in 26 states. “People are like, OK, this is the time to buy.”