The best time to go to Mosfellsbær is during the summer months, from June to August, or in the shoulder seasons of May and September, for milder weather and longer daylight hours.During June, July, and August, you'll experience the famous Midnight Sun, meaning nearly 24 hours of daylight. This allows for extended sightseeing and outdoor activities without feeling rushed. The temperatures are generally the mildest during this period, often ranging from 10°C to 15°C, making it pleasant for exploring the surrounding nature and the Golden Circle attractions without the chill of winter.May and September offer a good balance of decent weather and fewer crowds. In May, the days are getting longer, and the landscape is beginning to green up, while September brings lovely autumn colours and the potential to see the Northern Lights as the nights grow darker.