Construction of new homes and apartments, defying forecasts of a housing slowdown, shot up in January at the fastest pace in more than three decades.

The Commerce Department reported Thursday that building activity was up 14.5 percent last month when compared to December, pushing construction to a seasonally adjusted annual rate of 2.276 million units.

That was the fastest construction rate since March 1973, but it was expected to be a one-time blip caused by unusually warm weather in January that prompted builders to start work on more homes. Analysts are forecasting that housing construction will slow this year as the nation’s five-year housing boom quiets down.