A white Christmas at Portman Road as Town beat the Foxes and the weather to pick up a first Championship win in seven games.
The game survived two pitch inspections before kick-off but Blues skated to the points with first-half goals from David Norris and two from Jason Scotland.
Referee Stuart Atwell took the players off in the second-half and there were fears the game would be abandoned but after a 15 minute delay, the action resumed with Town having few scares on the way to the three points.
Marton Fulop returned in goal for Town, with another Blue who has worn Leicester colours, Damien Delaney, also recalled to the side. Shane O'Connor coming in for his first start since August.
Rory Fallon picked up a harsh yellow card inside the first two minutes, referee Atwell judging him to have caught Curtis Davies with his arm with the two going for a high ball.
Town were ahead though three minutes later, Leicester failing to deal with Jack Colback's free-kick and Norris burying a left foot shot past Chris Kirkland, who was making his debut after joining the Foxes on loan from Wigan.
Fallon sent a header at Kirkland as Town looked to have adapted to the difficult conditions the better of the two sides but on the quarter hour Blues had a slice of luck that has escaped Roy Keane's side recently, Mark Kennedy diverting Darius Vassell's header against the post following Paul Gallagher's free-kick.
O'Connor almost weaved his way into goal at the other end, Lloyd Dyer having a shot blocked for the visitors, then Fallon seeing a header cleared by Vitor.
Davies joined Fallon in the book after a foul on the New Zealand international before Town extended the lead on 26 minutes, Scotland beating Kirkland with a left foot shot to grab his first goal in nine games, the Foxes then making an immediate change with Steve Howard on for Dyer in a tactical switch by Sven Goran Eriksson.
Vassell had a left foot curler take a crucial deflection off Delaney to take it wide of the far post, Andy King then heading wide at the near post but Foxes paid the price for not clearing their lines in the ever worsening conditions,
Yuki Abe dispossessed by O'Connor inside the area and Scotland was on hand to divert the ball in from close range seven minutes before the break.
Fallon had a great chance to make it four on the stroke of half-time but saw his shot blocked and tried to find Colback with the follow up but Gallagher made a crucial interception.
Howard sent a volley wide in the opening exchanges of the second-half, Gallagher failing to get good connection with a left foot strike before referee Atwell called a halt to proceedings while the groundstaff cleared the lines.
An abandoned game looked a distinct possibility but the teams returned to arguably the biggest roar of the night, with the Leicester players clearly unhappy at having to play out the last half hour.
The Foxes had the ball in the net soon after the restart through Davies but not before the flag was raised for offside.
Connor Wickham replaced Fallon, Matty Fryatt for Gallagher with Jake Livermore also joining the action, Scotland making way.
Vassell and Howard both had chances for Leicester to reduce the arrears but they never looked likely to claw back the three goals and following a third change with Jack Hobbs on for Davies, they were forced to play the last 15 minutes with 10 men after Vitor limped off with a hamstring injury.
Wickham dragged a shot just wide on 85 minutes as he looked for his first goal of the season, Town's third substitute Carlos Edwards then setting up Grant Leadbitter whose shot was touched behind by Kirkland as Blues eased to three welcome points.
Town: Fulop, Zuiverloon, Smith, Delaney, Kennedy, Colback, Leadbitter, Norris, O'Connor (Edwards 76), Fallon (Wickham 60), Scotland (Livermore 68). Subs not used: Murphy, Peters, Brown, O'Dea.
Leicester: Kirkland, Naughton, Davies (Hobbs 69), Vitor, Cunningham, King, Abe, Wellens, Dyer (Howard 28), Vassell, Gallagher (Fryatt 64). Subs not used: Weale, Morrison, Oakley, Moussa.