A wave of high humidity and soaring temperatures is sweeping across northern China, leaving residents in a sticky, sweaty situation rarely experienced in the region.

In Beijing, phrases like "Beijing's tropical rainforest" and "stepping out in Beijing is like being licked by a cow" have taken off on social media as the city grapples with sauna-like conditions that show no signs of abating.

Relative humidity in Beijing briefly reached 100 percent on July 3, with most of northern China seeing humidity above 85 percent, according to Sun Jun, chief forecaster at the National Meteorological Center.

The unusual weather has led to a rare sight at the People's Park in Pinggu district, where a more than 40-year-old cedar tree has produced about 600 cones, Beijing Radio and Television Station reported on Monday. The conditions required for cedar trees to bear cones are strict, making this abundant yield highly unusual for areas north of the Yangtze River.

"Usually, northern regions experience hot and humid periods around late July to early August. This year, the northward shift and increased strength of the subtropical high-pressure system have accelerated this weather pattern," Sun said.

While temperatures in northern China have hovered around 30 C, which is not considered extremely high, the high humidity has made it feel much hotter, Sun said. He predicted that the "sauna days" could persist for at least another week.

Although sporadic showers and thunderstorms may bring brief relief, the hot and humid weather is expected to continue as warm, moist air from the southwest quickly replenishes the region's moisture, Sun said.

To help workers cope with the heat, the All-China Federation of Trade Unions has allocated nearly 40 million yuan ($5.6 million) to mobilize local trade unions to provide cooling relief to vulnerable groups, Xinhua News Agency reported on Sunday.

The nationwide effort includes cooling stations, cold beverages and heatstroke prevention medicine to protect workers exposed to sweltering conditions across industries.