To be honest, i stopped looking at the forecast many years ago, as quite often its wrong for my area. In the past I would make my mind over based on the forecast and often this disrupted my working day, as i may have decided to do something else instead and when it was wrong, i would lack the motivation to work as mentally i was prepared for something else.
Each night where im working the next day, the immersion goes on. Therefore if it does snow or the temp plumits, it makes no difference to my equipment and i can decide upon waking if its workable or not.