Futures for the Dow Jones Industrials gained 216 points, or 0.7%, early Wednesday to 30,571.
Futures for the S&P 500 hiked 34.25 points, or 0.9%, to 3,774.50.
Futures for the NASDAQ Composite index leaped 133.25 points, or 1.2%, to 11,479.25.
The rate-setting Federal Open Market Committee will conclude its two-day meeting on Wednesday.
The market is betting on a more than 95% chance of a 75-basis-point rate hike, the biggest increase since 1994.
The shift to price in a larger-than-usual rate hike came after headlines that Fed officials were contemplating such a move following a surprisingly hot inflation reading as well as worsening economic outlook.
In Japan, the Nikkei 225 faded 1.1% Wednesday. In Hong Kong, the Hang Seng gained 1.1%
Oil prices descended 55 cents to $118.38 U.S. a barrel.
Gold prices popped $21.30 to $1,834.40 U.S. an ounce.