Referee, Gary Sutton, inspected the pitch at 1.00pm and passed it fit to play warranted there was not serious deterioration in the weather conditions.
The Hillsborough ground staff were still working on the corner flag by the Kop and North Stands as the turnstiles were opened.
Chris Powell opted for a more attacking 4-4-2 shape, with Danny Haynes moved forward to partner Yann Kermorgant. Salim Kerkar returned on the left of midfield with Wilson, Frimpong and Jackson completing the quartet.
The wet and slippery conditions meant it would be a testing afternoon for keepers. Charlton made a bright start and came desperately close to taking an early lead when Haynes escaped Miguel Llera to put a ball across to the far post. Unfortunately, Kerkar was unable to apply the finishing touch.
Wednesday came more into the game, utilising the pace of their wide players, Michail Antonio and Jeremy Helan. Their quick, direct style brought the opening goal after 20 minutes. Michael Morrison was forced to concede a corner that Llera delivered from the left.
His flag kick was cleared to Rhys McCabe at the edge of the area. McCabe hammered the ball past Hamer’s right hand.
Chris Powell was sent to the stands eight minutes before the break after protesting that side side should have been given a penalty for a foul on Kermorgant.
Charlton’s early sparkle had evaporated by now though they thought they had restored parity just before the break. A sweeping move down the left involving Kermorgant and Kerkar saw Haynes slot the ball past Chris Kirkland, only for his effort to be ruled offside.
Lawrie Wilson was booked for a crunching challenge on Reda Johnson after 55 minutes. The caution will rule Wilson out of the Boxing Day clash with Ipswich.
Charlton came closest to an equaliser just past the hour mark when a move down the right, involving Wilson and Solly, was headed back across goal by Kermorgant to Haynes who failed to convert from close range.
The Addicks had to chase the game as time wore on and conceded a second in stoppage time when the lively Helan steered the ball past Hamer.
Wednesday thus ended a sequence of four consecutive defeats at Hillsborough, while the Addicks have now failed to score in their last three away games.
After the promising start, Charlton build up play was ponderous and they only looked like getting something from the game in fleeting cameos. Powell will have some serious thinking to do before Ipswich arrive at The Valley on Boxing Day.
Charlton: Hamer; Solly, Cort, Morrison, Seaborne; Wilson, Frimpong (Green 79), Jackson, Kerkar (Fuller 63); Kermorgant, Haynes (Hulse 79).
Subs (not used): Sullivan, Dervite, Pritchard, Wright-Phillips.
Booked: Wilson 57 (foul).
Sheff Wed: Kirkland; Buxton, Gardner, Llera, Reda Johnson; Antonio, Prutton (Lines 67), McCabe, Helan; O’Grady (Lee 75), Madine (Sidibe 86).
Subs: Bywater, Taylor, Maguire, J Johnson.
Goal: McCabe 20, Helan 90
Booked: Reda Johnson 12 (foul).
Referee: Gary Sutton (Lincolnshire).
Attn. 20,517.