There are many factors on a field which may influence a team’s decision of which end to defend. Not the least of those factors is wind.
When confronted with a strong wind, it is a good idea to play with the wind at your back during the first half of a game. Even if it does not directly affect the outcome of the game, it can have a huge psychological impact.
Playing WITH the wind will help your team on corner kicks, goal kicks, and other lofted balls. What’s more, having the wind at your back will make it easier for your team to move the ball down field, while at the same time, making it more difficult for the other team to do the same. Having the wind advantage can cause the opposition to adjust their tactics or it can even help your team get a quick lead. I’ve literally seen games where the team with the wind in their favor was able to safely move their goal keeper all the way up to the center line.
Having the wind at your back will allow your players to conserve energy, while your opponents will have to use more energy. This alone will likely offset the difficulty of playing against the wind in the second half.
Taking all this into account, it’s best to take advantage of the wind while you can, because wind conditions can quickly change.
Indeed, winds can very well switch directions giving you the advantage (or disadvantage) for both halves.