If the forecast is looking grim, why not spend some time at Henan Museum? You'll be fascinated by just how much you can learn about the past here.
You're spoiled for sightseeing choice in Jinshui District. Henan Museum is a great place to begin here, but there are plenty of other interesting spots to enjoy. Zhengzhou Museum, Erqi Memorial Tower, and Zhongyuan University of Technology are near the collection of historical artifacts and will round out your day nicely.
