Why does it get cold outside?

There are a few reasons why it gets cold outside.

* The Earth's tilt. The Earth's axis is tilted away from the sun by about 23.5 degrees. This means that during the winter, the Northern Hemisphere is tilted away from the sun, and the Southern Hemisphere is tilted toward the sun. As a result, the sun's rays strike the Northern Hemisphere at a lower angle, and the days are shorter. This means that there is less time for the sun to warm the Earth's surface, and the temperatures drop.

* The distance from the sun. The Earth's orbit around the sun is not perfectly circular, but rather elliptical. This means that the Earth's distance from the sun varies throughout the year. During the winter, the Earth is farthest from the sun, and during the summer, it is closest to the sun. This difference in distance means that the Earth receives less sunlight during the winter, and the temperatures drop.

* Atmospheric circulation. The Earth's atmosphere is constantly in motion, and this motion can help to distribute heat around the globe. However, during the winter, the atmosphere's circulation patterns can change, and this can lead to cold spells. For example, a strong polar vortex can cause cold air from the Arctic to descend over the mid-latitudes, and this can cause the temperatures to drop significantly.

All of these factors can contribute to cold weather outside.