It generally has three parameters: the lower limit of comfortable temperature, the range of comfortable temperature, and the upper limit of comfortable temperature. Comfortable temperature lower limit: If the ambient temperature is lower than this value, it will be too cold to fall asleep.
Comfort temperature range: The ideal temperature for using a sleeping bag, within this range, everything is just right.
Comfortable temperature upper limit: If the ambient temperature is higher than this value, it will be too hot to sleep.
Summary: It is recommended to choose a sleeping bag based on the lower limit of comfortable temperature. Compared with being frozen in the middle of the night, it is still a hot spot. When it is hot, you can open the zipper to cool down.
I hope it can be helpful for everyone to understand and use sleeping bags