Wall Street’s chilly January ended on a hot streak.

Stocks shot up by the most in five months on Friday, finishing with the biggest one-day gain of the year after Japan took more steps to boost its economy.

The Dow Jones industrial average soared nearly 400 points, to 16,466.30 — the second straight day of triple-digit gains for the blue chip index. The gains also amounted to the second weekly jump in a row.

Even with the optimistic end of the month, stocks are still down about 5.5 percent for the month, dragged lower by oil’s collapse and the weakening global economy.

The Dow wasn’t alone in its end-of-the-month party.

The Nasdaq rose 2.4 percent to 4,613.95, and the S&P 500 rose 2.5 percent to 1,940.24.

Crude oil jumped 1.6 percent to $33.74 a barrel — a 19 percent rise from a low close of $28.35 on Jan. 20.

The rally was sparked when Japan’s central bank surprised the markets by extending its asset purchasing program and slashing its interest rate into negative territory — essentially telling investors they have to pay for the privilege of holding the country’s debt.

The move puts the Asian economic powerhouse in league with European peers in easing monetary policy, even as the US Federal Reserve starts to raise its benchmark interest rate.

The markets also rose on the prospect that the Fed would go slow on raising rates again after the latest data suggested the US economy sputtered at the end of last year.

The nation’s gross domestic product grew at an annual rate of 0.7 percent in the fourth quarter, down from 2 percent the previous quarter.