Both games were severely affected by the almost gale-force conditions on Saturday morning, with Tony Carr's older side going down to a freak goal in the 73rd minute when goalkeeper Glenn Jackson was completely deceived by a shot from the edge of the area that appeared to be sailing over the bar before the wind caught it and the ball dropped into the net.
Freddy Eastwood and Elliott Ward had both come close to opening the scoring for the Hammers, but the weather played a huge part in proceedings and Carr was left to reflect on a miserable day for his team.
"It was an awful game," he admitted afterwards. "It simply wasn't a football match because the conditions meant that no football could be played and, as a spectacle, it was terrible.
"The goal that won it was out of nothing and would never have gone in had the wind not caught in, but you just have to accept these things and get on with it.
"That is only our first defeat since November, so the boys have had a good run, but it feels horrible to lose in this manner."
Team: Jackson, Khan, Dean, Dean, Ward, Lumsden, Ritchie (Fletcher 75), Akinsete, Carrick, Smith (Britton 75), Eastwood, Allen (Mehmet 60). Sub unused: Metitiri.
Peter Brabrook's under-17s, meanwhile, enjoyed the exact opposite to their older club-mates, as they saw off Birmingham thanks to a 75th minute goal from schoolboy Jason Blewitt.
Blewitt was just one of eight schoolboys in Brabrook's starting line-up and headed the winner when he rose to meet Craig Saunders' corner.
Prior to that, the Hammers had missed three good opportunities when Greg Pearson went close and Liam Parrington blasted over from close range.
Said Peter afterwards: "It was a good result for us, but not a good game with the wind really spoiling it. I was pleased with the boys, the back five defended really well and we created a few good chances in difficult conditions.
"Once again, we had a very young side out, with eight schoolboys in the team and two 14-year-olds on the bench. They all performed well considering the weather and it was a good win for us."
Team: Sealey, Wright, McClenahan, Parrington, Laws, Blewitt, Tucker, Cole, Collington (Lee 82), Pearson, Saunders. Subs unused: Read, Yao, Henry.