I always find the worst in in substantial chop or sort period swell with the wind coming from the beam. The boat generates spray out to the sides which gets blown back over the passengers. Spend long enough in this scenario, and your passengers will begin to have a severe dislike of the driver.
A few ways of dealing with this:
Slow down. Go slow enough that the spray to the sides is not generated, and it won't get blown back in. Downside: Takes a long time to get anywhere.
Run a zig-zag course directly into the wind, then slightly downwind. Downside is that it takes a long time to get anywhere, and it takes a fairly wide open area of water.
Get everyone bundled up in rain gear, and go. Downside: uh, let me think... The trip is over too fast? The kids will probably have a blast; the wife may not...