It's December in the Northern Hemisphere, when shorter days and the sun's lower angle reduce incoming solar heat. Earth's axial tilt directs less direct sunlight northward during this season, causing widespread cooling.
Seasonal Causes
The planet's 23.5-degree tilt means the Northern Hemisphere leans away from the sun in winter, spreading sunlight over a larger area for less warming per spot. Days are shorter, limiting heat buildup, while nights allow more radiative cooling.
Weather Patterns
Jet stream dips southward usher cold Arctic air into mid-latitudes, amplified by a sometimes disrupted polar vortex. Recent U.S. cold snaps, even in southern areas, stem from these meanders amid overall warming trends.
Personal Factors
Low body fat, anemia, or thyroid issues can make individuals feel colder than average. Layer up and check forecasts for polar vortex influences this week.