Yearly Monthly weather Grand Marais MNAtmospheric conditions in the heart of Grand Marais, Minnesota is consistently shifting. Whether it is clear or overcast, you can expect a selection of weather conditions throughout the year. Beginning in the breathtaking spring flowers blooming to the balmy and sun-soaked summertime days, to the colorful fall foliage, and the snowy landscapes in winter, Grand Marais, Minnesota offers a varied assortment of weather experiences during the year.