Northern Hemisphere

The Earth has two halves. The top half is the Northern Hemisphere.

This part of Earth has much land. It holds most of the land on our world. It also has many people living there.

Some parts are very cold. The Arctic is near the top. It has snowy winters.

Other parts are very hot. The tropical areas stay warm all year. They have rainy seasons too.

This half of Earth is a very big place.

The Earth is split into two halves. The top half is the Northern Hemisphere.

This half sits north of the equator. It holds 67.3% of all land on Earth. Large areas like North America and Eurasia are here.

Most of the world's people live in this half too. In 2015, about 6.4 billion people lived here.

The weather changes based on where you stand. The Arctic is at the very top. It is very cold with lots of snow.

In the middle, the temperate zone has mild weather. Near the equator, the tropical zones stay hot. These areas often have a rainy season.

Long ago, the north was much colder. Huge ice sheets covered many lands. These were called glacials. The last big cold period ended 10,000 years ago. Now, we live in a warmer time called the Holocene.

This part of Earth is a very big and busy place.

The Northern Hemisphere is the top half of our planet.

It is the part of Earth that sits north of the equator. This half of the world holds most of the land. In fact, it contains 67.3% of all Earth's land. This includes the entire continent of North America. It also holds the whole mainland of Eurasia.

Some other places like part of South America and Africa are here too. Because there is so much land, most people live in this half. In 2015, about 6.4 billion people lived in the Northern Hemisphere. That is about 87% of all the people on Earth.

Weather and seasons work in a special way here. The Earth tilts on its axis by about 23.4 degrees. This tilt causes the lengths of days and nights to change. It also causes different temperatures throughout the year. Summer usually goes from the June solstice to the September equinox. Winter goes from the December solstice to the March equinox.

The weather feels different depending on where you stand. The Arctic is at the very top near the North Pole. It has cold winters and cool summers with lots of snow. The temperate zone has milder weather between the Arctic and the tropics. Tropical areas near the equator stay hot all year.

Long ago, the Northern Hemisphere looked very different. During the Pleistocene, the north went through many cold phases. These were called glacials or ice ages. Huge ice sheets grew to be 3 or 4 kilometers thick. These sheets were so big they lowered the sea level by 120 meters.

These cold periods happened every 40,000 to 100,000 years. They were separated by warmer times called interglacials. The last big cold period ended about 10,000 years ago. We are living in a warm period now called the Holocene.

Moving water and air also follow specific patterns here. A thing called the Coriolis effect makes objects turn to the right. This effect changes how winds and ocean currents move. Trade winds blow from east to west just above the equator. These winds pull water to create currents that flow westward. Eventually, these currents bend to the right and head north. At 30 degrees north, different winds push them back east. This creates a large, clockwise loop in the ocean.

Looking up at the sky is also unique in the north. If you look at a sundial, the shadow moves clockwise. At noon, the Sun usually appears in a southerly position. The Moon looks different here than it does in the south. The North Pole also faces away from the center of our galaxy. This makes the Milky Way look thinner and dimmer. This is actually helpful for people watching deep space. It means they are not blinded by the bright center of the galaxy.

The Northern Hemisphere is the half of Earth located north of the equator.

This region is defined by its position relative to the equator and the Earth's axial tilt. For other planets in our Solar System, the term "north" refers to the celestial hemisphere relative to the invariable plane of the Solar System. The Northern Hemisphere is a massive part of our planet. It contains 67.3% of Earth's total land area. This is significantly more than the Southern Hemisphere, which is 80.9% water.

Because of this land distribution, most of the world's continents are located here.

Climate and seasons in this hemisphere are driven by the Earth's axial tilt. The Earth tilts at an angle of 23.439281 degrees. This tilt causes seasonal variations in day and night lengths. It also causes changes in temperature throughout the year. Winter is conventionally defined from the December solstice to the March equinox. Summer is the period from the June solstice to the September equinox. These dates change slightly each year due to the difference between the calendar and astronomical years. The temperature changes often lag behind the changes in day and night length.

Different zones within the hemisphere experience very different environments. The Arctic is the region around the North Pole at 90 degrees latitude. It features cold winters and cool summers with much precipitation as snow. Inside the Arctic Circle, at 66°34′ latitude, the Sun may never set in summer or never rise in winter. Between the Arctic Circle and the Tropic of Cancer (23°26′ latitude) lies the Northern temperate zone. This area has generally mild seasonal changes, though weather can be unpredictable.

Tropical regions exist between the Tropic of Cancer and the Equator. These areas are hot all year and have rainy and dry seasons.

Movement in the Northern Hemisphere is influenced by the Coriolis effect. This effect causes objects moving across or above the surface to turn to the right. This force creates large-scale clockwise-turning gyres in ocean circulation. You can see these patterns in the North Atlantic and North Pacific oceans. Trade winds blow from east to west just above the equator. They pull surface water westward, creating currents that eventually bend right and head north. At 30 degrees north latitude, the westerlies push these currents back east. This creates a closed, clockwise loop of water.

Atmospheric pressure also follows these patterns due to the Coriolis effect. High-pressure weather cells feature clockwise air circulation. Conversely, air rising from the surface creates a low-pressure region. This rising air draws other air inward in a counterclockwise pattern. Because of this, hurricanes and tropical storms spin counterclockwise in the Northern Hemisphere. These massive low-pressure systems are powerful drivers of weather. Oceanic currents also change weather patterns for many coastal areas. Events like the El Niño–Southern Oscillation can impact these northern coasts.

History shows that the Northern Hemisphere has undergone massive climate shifts. During the Pleistocene, which lasted 2.5 million years, the region experienced many cold phases. These are known as glacials or the Quaternary ice age. These phases involved significant advances of continental ice sheets in Europe and North America.

Glacials occurred at intervals of 40,000 to 100,000 years. They were separated by shorter, warmer interglacials lasting 10,000 to 15,000 years. These ice sheets were 3 to 4 kilometers thick. They were so heavy they lowered sea levels by about 120 meters. The last major cold episode ended about 10,000 years ago. We are currently in an interglacial period called the Holocene.

Human life is heavily concentrated in this hemisphere. As of 2015, the Northern Hemisphere was home to approximately 6.4 billion people. This represents about 87.0% of the Earth's total human population of 7.3 billion. The hemisphere includes all of North America and the mainland of Eurasia. It also contains about two-thirds of Africa and a small part of South America. Looking at the sky, the North Pole faces away from the Galactic Center of the Milky Way. This makes the Milky Way appear sparser and dimmer here. This characteristic makes the Northern Hemisphere excellent for deep-space observation.