Why Is February So Cold?

Why Distance from the Sun Doesn’t Cause Winter

Although I was taught that Earth’s distance from the Sun averages about 93 million miles, in reality, this distance varies from 91.4 million miles in early January to 94.5 million miles in July—so Earth is indeed closer to the Sun during our winter.

But when you think about it, Earth’s distance from the Sun cannot be seen to be the reason for the seasons, as when it is winter for me in Pennsylvania, it is summer for my friend in Australia. As we all know, seasons in the Southern Hemisphere are the opposite of those in the Northern Hemisphere.

How Earth’s Tilt Affects Sunlight and Seasons

Instead, the answer lies in the 23.5-degree tilt of Earth’s orbit as it revolves around the Sun (see below).

Using a Flashlight to Understand Sunlight Angles

 If you point a flashlight straight ahead, you will see a circle of light, with the brightest light in the center. Right?

If you tilt the flashlight, its light is more diffuse and weaker away from where it is shining directly.

The weaker light in the case of the Sun and our solar system means that Earth is receiving less energy from the Sun, which is why the weather is colder and the daylight hours are shorter in winter.

Seasonal Lag: Why February Is Colder Than December

Since the amount of sunlight is at its minimum at the winter solstice, which occurs around December 21 or 22, you might expect that day to be the coldest of the year, on average. But instead, the coldest time of year in the Northern Hemisphere occurs in February, nearly 2 months later.

The Role of Land and Water in Winter Temperatures

This happens because while Earth receives energy from the Sun, it also emits energy into space. And Earth’s Northern Hemisphere emits more energy than it receives for nearly 2 months after the winter solstice, so temperatures continue to trend downward. Think about what happens when you turn off the burner on an electric stove—it does not cool down to room temperature instantly but instead remains hot for a while until it finally reaches room temperature.

Similarly, Earth retains warmth from the previous summer, and it takes more time to cool down after sunlight fully reaches its seasonal minimum.

Key Takeaways About Winter Weather Patterns

Because land and water have different specific heat capacities, they warm and cool at different rates. Thus, oceans and other large bodies of water heat and cool more slowly than the land surrounding them. This is why a sea breeze from the ocean brings cooling in the summertime and why the Great Lakes can produce snow squalls in the winter.

So, the seasons are not caused by changes in Earth’s distance from the Sun but instead by Earth’s tilt in its orbit. There is a lag between when incoming solar energy reaches its high and low points and when we record the warmest and coldest temperatures because Earth receives energy from the Sun and emits energy into space.