24 degree temps will easily reduce tire pressure that far, but since the one tire was low I would check to see how much the other really dropped. Adding a Nitrogen fill to you tires will help eliminate pressure issues and since the actual molicules are larger than air it is said they do not leak through the rubber like air will. The moisture present in the regular air fill is the reason for the pressure change in cold and hot extremes.

Check the valve cores first though with a little soapy water.