The bridge in Shangluo in Shaanxi province partially collapsed on July 19 “due to a sudden downpour and flash floods”, state news agency Xinhua reported at the time.
A three-lane section of the bridge plunged into a river, CCTV footage showed, dumping cars and trucks into the torrent below.
On Friday, authorities revised the death toll up from 12 to 38, with 24 still missing, according to Xinhua.
Authorities have also confirmed that 25 vehicles were swept away when the bridge collapsed, CCTV reported.
China is enduring a summer of extreme weather, with heavy rains across the east and south coming as much of the north has sweltered under successive heatwaves.
Climate change, which scientists say is exacerbated by greenhouse gas emissions, is making such extreme weather phenomena more frequent and more intense.
In May, a highway in southern China collapsed after days of rain, leaving 48 dead.
Heavy rains this week in central China have also left at least 30 people dead, state media said on Thursday, the same day that weather authorities reported that July had been China’s hottest month since record-keeping began six decades ago.
MNA/PR