That's the catch with this particular social media app. BeReal doesn't have any single set time that it will prompt its users to take photos. In fact, it changes every single day. The only constant is that it will prompt a user twice a day, but that time could vary completely. For example, you could post at 3 p.m. and 11 p.m. on one day, and then be asked to post at 6 a.m. and 5 p.m. the next. This air of surprise leans heavily on BeReal's mission to be as authentic as possible.