With a historic summer heat wave sweeping China, Coca-Cola and McDonald's are teaming up to cool down thirsty consumers with a creative promotion.

As temperatures have risen these last few weeks, Sprite launched the Project 35°C campaign in collaboration with the popular weather service app, MojiWeather, and the 2,400-plus McDonald’s restaurants in China.

Here's how it works: Consumers are eligible to receive Sprite in cities where the temperature tops 35°C (95°C). Freebies are limited to one device per day. Consumers retrieve QR codes from the MojiWeather mobile app to redeem at a nearby McDonald’s.

Since launching on June 28, consumers have claimed more than 10 million cups of Sprite online, bringing more than 2 million guests to McDonald's outlets. In July, single-serve sales of Sprite were up 23 percent over July 2016. 

“Our goal was to find our customers in the most relevant scenarios in their daily lives, and share with them the feeling of Sprite: 'Sudden refreshment, refreshing to the core, freeing your heart,'” said Joanna Lu, vice president, marketing, Coca-Cola China. 

The peak temperature in Hangzhou, Xi’an, Shanghai, Hefei and Nanjing had reached or exceeded 40°C by July 28. Six provinces in the country have hit record-high temperatures this year.