Your WeChat Out balance is displayed in the local currency based on your registered region and linked mobile number.
For users in the United States, Canada, Singapore, China‘s mainland, Hong Kong SAR, Taiwan (China), Japan, Britain, and Eurozone regions, the balance is displayed in their local currency. For users in other regions, the balance is displayed in U.S. Dollars by default. Future updates may adjust the display currency based on the region of your Apple ID or Google Play account.
Note: If your WeChat or Apple ID account region changes, you must use up your existing balance before topping up again.