yeah, ± is used for giving an exact two values (or the range between them) such as 6±2 minutes being 4 minutes OR 8 minutes (or the range between them). just using ± and then a number means you are either adding or subtracting that which is kinda funky here (sorry I'm a math nerd)
Sadly weather-chan was also on a date, but her date left middle of the date despite everything going so well. So weather-chan was unable to hold back her tears.