What lubricating grease should be used in automotive wheel bearings under low ambient temperature conditions?

Most  lubricating greases formulated for use in automotive wheel bearings are NLGI 2 grade and are designed to operate at temperatures as low as -40 °C (-40 °F).  The NLGI GC-LB or SAE J310 specifications require the grease to operate at that temperature.  For continuous operation at extremely low temperatures (below -40 °C/-40 °F), a product containing a synthetic base fluid may be considered.  In addition, a softer consistency grease (NLGI 1 grade) may be needed.