During the month of May, the daylight hours in Iceland can range from about 18 to 21 hours per day, depending on where you are in the country. In June, the longest day of the year (the summer solstice) falls on June 20th or 21st, and in some parts of Iceland, the sun may not set at all during this time, giving you nearly 24 hours of daylight. It's a pretty unique experience, so make sure to plan accordingly and take advantage of all that daylight!