WASHINGTON — The World Bank has downgraded its estimate of the world’s economic expansion in a new forecast released Tuesday, with developing economies posting disappointing growth rates and the frigid winter in the United States and the crisis in Ukraine weighing on growth, too.

The development institution, based in Washington, now anticipates global growth of just 2.8 percent in 2014, picking up to 3.5 percent in 2016. In its previous forecast, made in January, it estimated that the global economy would grow 3.2 percent this year.

“This is the third year in a row that developing countries have grown less than 5 percent,” said Andrew Burns, the lead author of the World Bank report. “It frankly is the third year in a row that we’ve been disappointed in the actual outturns.”

The World Bank sharply downgraded its estimate for growth in the United States this year to 2.1 percent from 2.8 percent, while also cutting its collective forecast for small high-income countries, including Croatia and Hong Kong. It mostly maintained its estimates of growth in other major advanced industrial economies, with the euro area expected to expand about 1.1 percent and Japan about 1.3 percent.