2005 c240 mb engine won't turn over when it is really cold outside. on a warmer day it starts fine. this winter is the first time it has done it. brand new battery new spark plugs. you can hear it

2005 c240 mb.  on cold days it won't start.  it almost turns over and you hear it
trying but it just doesn't make the final connection with engine to start.  I have
brand new battery and brand new spark plugs just installed.  As soon as the
weather warms up it starts as normal.  There is definitely something about the
cold weather.