Bombus ternarius is one of the most commonly observed bumble bees in the northern two-thirds of Minnesota, and is generally absent in southwestern prairie biome. New queens (gynes) establish a nest belowground at various depths, often selecting abandoned rodent or small mammal burrows. The gynes typically emerge from hibernation in mid-spring, workers in mid-June, and males in mid- or late July. 

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Bombus ternarius has a light yellow hairs on the thorax and black hairs between the wing bases (females and males), and black extending in a T-shaped pattern down the middle of the thorax (females). The first abdominal segment or tergite (T1) with yellow hairs, the second and third tergites (T2 and T3) with bright orange hairs, the fourth tergite (T4) with yellow hairs, and the fifth (T5) with black hairs. Males have yellow hairs on the vertex (back of the head or "neck") and face; females have a mix of black and yellow hairs on the vertex and face. The wings are medium to dark brown.