Jose Mourinho’s men went six points clear before this game kicked off with a win 2-0 over West Ham but City responded in emphatic style.
They had the game sewn up by half-time with three goals in the opening 34 minutes.
West Brom came into this game with just one win from their last 13 matches and their nerves were clear from the start as City took the lead inside four minutes.
Christmas may have passed but West Brom’s goalkeeper Ben Foster still was giving out gifts by spilling a routine cross right under the nose of Fernando six yards from goal.
The City midfielder needed no second invitation and cleverly hooked the ball into the unguarded net.
Things went from bad to worse for the hosts in front of a restless home crowd when Joleon Lescott, who endured a nightmare game against his former club, fouled Silva as he jinked his way into the penalty area.
From the spot, Toure confidently stroked the penalty into the corner of Foster’s net.
Despite being two goals down with just 14 minutes on the clock, West Brom responded well and Saido Berahino went close to reducing the deficit two minutes later but fired wide after being played through by James Morrison.
Silva made the West Brom forward pay for that miss on 34 minutes when he got the goal his performance merited.
Conditions became tricky as the snow began to settle and the game suffered in quality as a consequence but referee Mike Clattenburg never looked like considering an abandonment to the dismay of the home crowd who were chanting “let it snow.”
West Brom had the better of the play in the conditions but some wayward finishing by Sessegnon and a missed header from three yards out from Lescott failed to give West Brom a base to launch a comeback.
Ideye did find the net late on for the hosts – his first goal for the club since his £10m move from Dynamo Kyiv – but it was hardly one to remember as Joe Hart flapped at a cross and the ball bounced off the back of the forward’s head and into the net.