Alan Pardew's future hangs in the balance after Troy Deeney's second half-strike condemned West Brom to their fifth successive Premier League defeat.
West Brom enjoyed the greater opportunities at Vicarage Road, but Watford captain Deeney scored against the run of play with just 13 minutes remaining to heap further pressure on manager Pardew.
The defeat left the Baggies rooted to the foot of the table, eight points from safety with just nine matches remaining.
A number of Watford supporters helped clear the snowy remnants of Storm Emma from in and around Vicarage Road on Saturday morning to ensure their club's fixture did not fall foul of the big freeze, but, on the evidence of the opening period here, they might have wondered why they bothered.
Indeed, it was the Baggies who had the best of a desperately uneventful first 45 minutes, with Grzegorz Krychowiak's early shot seemingly destined for the back of the net but for a fine block from Adrian Mariappa.
Salomon Rondon also headed narrowly over, while Chris Brunt, restored to the starting line-up despite his criticism of Pardew following the defeat against Huddersfield, saw his left-footed set piece ripple the roof of Orestis Karnezis' net.
Watford had to wait until seven minutes before the interval for their first significant effort. Roberto Pereyra played Daryl Janmaat through on goal, but his side-footed effort was expertly saved by Ben Foster's outstretched leg.
West Brom were on the attack again after the interval, with Rondon spurning two good chances in as many minutes to break the deadlock.
Rondon, who has scored just four times in the league this season, beat the offside trap only to see his shot turned round a post for a corner with 51 minutes gone.
From the ensuing set-piece, an unmarked Jonny Evans then hit the woodwork when his hooked effort from the byline cannoned of Karnezis and on to his near post. Rondon then headed well wide from Kieran Gibbs' cross when he really should have found the target.
Despite West Brom's early second-half opportunities, the home side slowly began to enjoy greater possession, but without testing Foster in the Baggies' goal.
And it was the visitors who again came within inches of scoring as Matt Phillips crossed from the right-hand side, but Janmaat did enough to prevent Jay Rodriguez from scoring at the near post.
At the other end, West Brom then had Gibbs to thank for keeping the score level after he cleared off the line from Stefano Okaka.
But his good work was undone only moments later when Deeney made the game's pivotal contribution, scoring the goal which could signal the end for Pardew.
Played through by substitute Will Hughes, and with only Foster to beat, the Hornets skipper made no mistake with an emphatic finish after 77 minutes.
The home and away supporters united in a chorus of 'You're getting sacked in the morning' to Pardew, as Watford secured their third home victory in as many games under new boss Javi Gracia.