Which month is associated with the lowest 300 mb heights above the North Pole?

• A. June
• B. January
• C. December
• D. February

Answer: (B)

The month associated with the lowest 300 mb heights above the North Pole is January. During this time of year, the polar regions experience the coldest temperatures due to the tilt of the Earth, which results in less direct sunlight hitting the areas at high latitudes. As temperatures decrease, the density of the air also decreases, leading to lower heights at the 300 mb pressure level.

These lower heights indicate a stronger and more unstable polar vortex during January, which can result in more pronounced weather patterns in the Northern Hemisphere. The polar vortex is generally stronger and more confined in the depths of winter, causing lower heights at this altitude.

In contrast, during the summer months, such as June, the atmosphere warms, which leads to an increase in height at the 300 mb level due to the expansion of air as it warms up. December and February are still winter months, but January typically marks the peak of winter intensity in the polar regions, resulting in the lowest average heights observed in the atmosphere at the 300 mb level.