The best time to visit Iceland depends on what you want to do. For those looking to take in the natural beauty, late spring and summer (May through August) is the best time to visit. The long days and mild temperatures make it ideal for outdoor activities such as hiking, sightseeing, and whale-watching. For those looking to experience the Northern Lights, winter (September through April) is the ideal time to visit. The days are shorter, but the skies are usually clearer, making it easier to spot the aurora borealis.