well,this yr i worked on 46 small frescos from summer through to winter sun rain and shine.. i did notice small changes in drying,but not all that dramatic. in warmer weather i always keep a small spray pump at hand with distiled water, this seems to retard the drying giving me more time. as fare as below 0 temps.. i would not know australia does not seem to get that cold .thicker layers do help ,but only on ur roughcast layers ,the intonico should stay the same ,to aviod hair line cracks.. good luck down under.............