The climate in Duluth falls under a mild subtropical climate, characterized by mild winters and hot, humid summers. This city is generally considered humid, but compared to the maritime climate of South Korea, it is relatively dry. Thanks to its continental climate, the perceived temperature in Duluth is very high, leading outsiders to nickname it Hotlanta.

Winters are very mild with little snowfall. In fact, indoor humidity during winter can drop below 15%, making it quite dry. While the average humidity in South Korea during winter is around 35%, Duluth experiences much drier weather.

By February, the weather is warm enough for short sleeves and shorts, with only about two weeks that can truly be called winter. From November to January, the weather resembles late autumn in South Korea, and it is rare for temperatures to drop below freezing even in January, with lows around 1 degree Celsius.

Summer continues with hot and humid weather. The summer season lasts from April to October, with maximum temperatures exceeding 30 degrees Celsius. Although temperatures drop at night, it remains warm. Humidity is high, but it is not as oppressive as in South Korea, and it still feels relatively less humid. Summer temperatures exceed 30 degrees Celsius, but the perceived temperature may feel even higher.

Winter in Duluth feels like a cool spring day, and except for January and February, it resembles mild autumn weather. It is rare for temperatures to drop below zero, and while cold snaps can occur, the average temperature is around 1 degree Celsius. The winter weather in Duluth is similar to that of Jeju Island, with significant temperature variations, and the lowest temperatures in January do not drop below freezing, allowing for warm weather similar to autumn.

While Duluth does not receive much snow, occasional snowfall can lead to significant traffic congestion. In January 2010, about 2 inches of snow fell, paralyzing the city, and in January 2011, schools were closed due to snow. Nevertheless, winter in Duluth sees more rain than snow. Precipitation is high during winter, with frequent rain similar to summer, but there are no continuous monsoons like in summer. Instead, heavy rain can occur with storms, sometimes causing power outages.

Due to its continental climate, Duluth experiences high perceived temperatures. While summer temperatures are very high, well-air-conditioned indoor environments can maintain a comfortable atmosphere without sweating. Compared to the humid summers in Asia, the perceived temperature feels lower, and the continentality results in drier weather compared to coastal cities.

The climate in Duluth is classified as mild subtropical, characterized by mild winter weather and hot, humid summer weather.