Paul, it has a higher cloud/gel point than #2, so some caution must be exercised when running blends higher than b50 or so. If you are using b20, you are good to about -5F or so, but if you are thinking of using b20 in those types of temps, just get a jug of powerservice arctic express biodiesel antigel... . it's specifically made for b20. If you are using b15 or less, I would simply treat it like regular diesel. I've run my mb at -5 with b20 and never noticed a difference. Oh , aside from a much quieter idle !