It is quite cold in Jordan between December and March.  There is also rain and occasionally snow.  One should be prepared to dress and sleep warmly.  We would suggest good wool clothing and socks, a thick coat, and purchase of a gas, kerosene or electric heater.  Note regarding appliances that the current here is 220v. with 50 cycles.  For most foreign appliances you will need to purchase transformers.  Transformers are readily available here in Amman.