How do jet streams typically behave during summer?

Jet streams are fast flowing air currents located in the atmosphere, typically at altitudes between 30,000 and 40,000 feet. During the summer months, jet streams usually weaken and shift northward. This behavior is primarily caused by the significant temperature differences between the equator and the poles; in summer, the poles receive more sunlight and warm up, thus reducing the temperature gradient that drives the jet streams.

As the jet streams shift north, their influence on weather patterns changes, often leading to different climatic conditions compared to those in the winter months. The weakened state of the jet streams during summer can lead to more stagnant weather patterns, resulting in prolonged periods of calmer weather in many areas.

In contrast, other potential behaviors such as strengthening or shifting southward usually pertain to winter conditions when temperature gradients are more pronounced due to colder polar air. Disappearance entirely is also not accurate, as jet streams do not completely vanish; instead, they simply change in strength and position relative to seasonal temperature variations.