Grand Marais Weather in August 2023 Weather2VisitClimate inside Grand Marais, Minnesota is always changing. Whether it's bright or overcast, anticipate an array of climate conditions throughout the year. Beginning in the gorgeous springtime flowers blossoming to the hot and sun-soaked summertime days, to the vibrant fall foliage, and the snow-covered landscapes in winter, Grand Marais, Minnesota provides a wide variety of weather experiences during the year.