The headwinds that China’s foreign trade has faced for months -- sluggish domestic and global demand -- likely persisted in January. That means, the trade surplus, the difference between outbound and inbound shipments, probably increased again in January as imports dropped farther than exports.

China's exports likely dropped 2.4% year-over-year in January in dollar terms, according to a median forecast of 13 economists polled by The Wall Street Journal. That’s steeper than December’s 1.4% decline year-on-year, official data...