China’s bureau of meteorology has blamed a data glitch after this week’s forecasts of wild swings in temperature for 13 provinces turned out to be completely wrong. Across the country, many people got a shock when they checked the forecast on weather apps on Monday morning to see temperatures would rise or fall in their areas by more than 20 degrees Celsius (68 Fahrenheit) in a single day this week during the Lunar New Year holiday. The weather apps use data provided by the China Meteorological Administration, which said the glitch affected provinces including Shandong, Jiangsu, Gansu and Hainan. More cold weather on the way for Hong Kong, but Lunar New Year set to be warm In the city of Jinan, capital of Shandong, the forecast showed three days of unusually warm weather starting on Thursday, when it would climb 20 degrees to a high of 28 degrees Celsius. But in Linyi, also in the eastern province, the temperature was forecast to plunge by 20 degrees on Wednesday. The drastic change had many people talking about the weather on social media, and wondering if summer was coming early. “Four seasons in one province ... It doesn’t feel like we live in one hemisphere,” a Shandong resident wrote on Weibo, China’s version of Twitter. Heavy snow causes travel chaos in central and southern China The weather bureau said it had been inundated with calls from the public concerned about the unusual forecasts on Monday. The bureau later posted a notice on its official Weibo account saying the forecasts were wrong and had been caused by bugs in its raw data. It said the problem had been resolved by 10.10am on Monday. Warmer temperatures were forecast for most regions this week but they would drop again from Friday, the bureau said. “The glitch has been fixed – please check the updated forecasts and keep calm. You won’t need your summer clothes ... be prepared for it to get colder on Friday,” the bureau said in the notice. It did not give further details of the data problem or explain why it affected only 13 provinces.