BEIJING (Reuters) - President Barack Obama will visit China in mid-November, the new United States ambassador to Beijing said on Saturday, setting a date for a big summit likely to tackle the global economy, North Korea and climate change.

Washington's new envoy to Beijing, Jon Huntsman Jr., told reporters Obama "is going to be visiting in the middle of November," but he did not give specific dates.

Until now, neither Beijing nor Washington has publicly given such a firm time for the big visit.

It means the U.S. President is likely to go to Beijing and perhaps other regional capitals after the Asia-Pacific Economic Cooperation leaders' summit in Singapore on 14-15 November.

Huntsman, speaking at his residence after arriving in the Chinese capital, said relations between the two economic and political powers were improving.

"By the end of the year, we should be in better shape than ever before between the United States and China," he said, in a speech that switched between English and fluent Mandarin Chinese.

But Obama's summit with Chinese President Hu Jintao will also confront thorny differences with Beijing on trade and economic policy, North Korea's nuclear weapons ambitions, and climate change policy, with nations seeking to agree in December on a new international pact to reduce greenhouse gas emissions.

China has chided Washington for policy failings exposed by the financial meltdown, has resisted U.S. calls to pressure Pyongyang with tougher sanctions, and said rich countries must lead the way in greenhouse gas emissions cuts.

"There has never been a more important period for the United States and China to get along," said Huntsman. "The world today more than ever before relies too much on a healthy and stable U.S.-China relationship."

With his strong personal ties to China and fluent Mandarin, Huntsman is likely to be a high-profile envoy.

Huntsman mastered Chinese as a missionary in Taiwan. He was the Republican governor of Utah before accepting the ambassadorship, and also worked as a U.S. trade official.

Huntsman's family founded chemical company Huntsman Corp, which has operations in China, including a factory in Shanghai. One of his seven children was adopted from China.

(Reporting by Chris Buckley; Editing by Jerry Norton)