Forecasting temperatures accurately takes practice but there’s a certain time of day where it can get tricky… and that’s overnight.
The sun heats the atmosphere from the ground up throughout the day. At night that heat escapes into space and we cool. This is called radiational cooling. When there’s an abundance of cloud cover, it can act as a lid or a blanket to keep some of that heat from escaping into space. Under cloud cover, overnight lows can be much warmer than areas that have clear skies. On clear nights, all of the warmth is able to escape our atmosphere, which cools us even faster