In the last few months I have acquired a few potted cacti and a couple of succulents that, according to care sites should be kept inside if temperatures get lower than 40 or 50 degrees F ( 4 to 10 degrees C). I live in Southern California and the temperatures at night can dip below 50 F but is 60 to 80 in the day. Later in the winter the highs will dip below 50 from time to time.
I don't know how to interpret this, should I assume that the plants should be brought inside when high for the day is below 50 or if the the low is below 50 at any time. I don't have a sunny window inside so would like to keep them outside as much as possible.