When I was doing all the grocery runs by bike the extra weight made it far more difficult than any winds I encountered. The handling is more difficult, rear heavy, swaying, hard to keep a straight line up hills. As I recall it was usually heavier than 30 pound loads though. With just 30 I think it would be easier than riding against a good stiff wind, say 15-20 mph. Relative to just riding the bike that is, irrespective of speed.