The best time to visit is from June through August, when the weather is mildest (though you should still anticipate cool, wet, and sometimes stormy weather), daylight hours are longest, and the wildlife is most abundant. Deciding when to visit depends on what you hope to experience. For instance, birding is often best in May and June, when migrants arrive in large numbers. The peak wildflower season is usually short, particularly in the Arctic, when most flowers may not blossom until mid-June and then go to seed by late July. Salmon runs vary from region to region, so it's best to do your homework before choosing dates. The shift to autumn's bright colors may begin in early to mid-August. And northern lights are "hidden" for most of the summer, because of the long daylight hours.