Many survivalists think they need a single bug out bag. They will grab that bag, no matter the season. If you only have one bug out bag, you are going to have problems in extreme temperatures. You need to create a winter and summer bug out bag. That way, you can grab the bag you need for the season.
Each bag should contain the tools, equipment and supplies you need to survive that season. For instance, in the winter time, you will need supplies to keep you warm. In the summer, you will need additional fluids. Pack accordingly so you can make it out there, regardless of the season.
If you try to fit it all into one bag, you will make the mistake of packing too much into one bag. That will make your bag too heavy, which will reduce mobility. By making the separate bags, you can take everything you need without making your bag too heavy.