The Earth’s axis is the imaginary line through the centre of the Earth between the South and North poles about which the Earth rotates. This axis is tilted slightly compared with the way the Earth orbits the Sun. We get different seasons (winter, spring, summer and autumn) because the Earth’s axis is tilted.

The seasons in the Northern Hemisphere are the opposite of those in the Southern Hemisphere. This means that in Argentina and Australia, winter begins in June. Seasons occur because Earth is tilted on its axis relative to the orbital plane, the invisible, flat disc where most objects in the solar system orbit the sun.

The difference between these two latitudes is 74° – 16° = 58°. Since the tilt of Earth is less, there would be less variation in the tilt of Earth and less variation in the Sun’s paths throughout the year, so there would be milder seasonal changes.

When the Earth’s axis is tilted toward the sun for the Northern Hemisphere, the people in the Northern Hemisphere experience summer, while at the same time, the Southern Hemisphere is tilted away from the sun and the people there experience winter.

During summer, the North Pole is tilted towards the sun. As a consequence, the sun’s path is higher in the sky, causing the northern hemisphere to receive more light and heat. Now, the sun’s path is lower in the sky, causing the northern hemisphere to receive less light and heat. This makes the days shorter and colder.

The Sun is currently in the constellation of Gemini. The current Right Ascension of The Sun is 06h 17m 45s and the Declination is +23° 22′ 18” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom [change]). The current magnitude of The Sun is -26.71 (JPL).

Having the sun directly overhead can happen only between the Cancer and Capricorn tropics. That is, only the places between 23.5° of latitude north and 23.5° of latitude south. On the Cancer tropic (23.5° latitude north) it will happen once every year, on the day of the northern hemisphere solstice (about June 21st).

The sun is directly overhead at noon. At the Decrmber Solstice, the sun is always to the south, and never quites get directly overhead. The equator has 12 hours of sunlight every day of the year.

the equator

subsolar point

Answer: For continental U.S. the answer is never. Since the Earth’s rotation axis is tilted 23.5 degrees with respect to its orbital motion around the Sun, one would have to be less than 23.5 degrees above or below the equator to have the Sun pass directly overhead (once per year).

HONOLULU, Hawaii (HawaiiNewsNow) – This month, many areas around the Hawaiian Islands are going to experience the phenomenon known as “Lahaina Noon.” This is when the sun is directly overhead and vertical objects like flagpoles do not cast a shadow.

The equinoxes happen in March (about March 21) and September (about September 23). These are the days when the Sun is exactly above the Equator, which makes day and night of equal length.

While the solstices result in a change of the length of night and day, the equinoxes do not. The summer and winter solstices result in the longest and shortest day of the year respectively while the equinoxes result in an equal amount of daylight and darkness received all across the earth.

The solstice (combining the Latin words sol for “Sun” and sistere for “To Stand Still”) is the point where the Sun appears to reach either its highest or lowest point in the sky for the year and thus ancient astronomers came to know the day as one where the Sun appeared to stand still.

An equinox is the exact instant when the Sun is directly overhead the Equator and the Earth’s rotational axis is tilted neither towards nor away from the Sun. In any given calendar year, this happens twice, first around March 20 (March equinox) and then again around September 22 (September equinox).

In 2021, the March equinox happens on Saturday, March 20, at 5:37 A.M. EDT. In the Northern Hemisphere, this date marks the start of the spring season.

(The opposite is true in the Southern Hemisphere.) In other words, it takes Earth less time to go from the autumnal equinox to the vernal equinox than it does to go from the vernal equinox to the autumnal equinox. Due to all this, the seasons range in length from about 89 days to about 94 days.

However, every once in a while, the autumn equinox can occur on Sept. 21 or 24. This happens because the length of a calendar year (365 days) is not equal to the time it takes for Earth to travel around the sun (365.25 days). However, leap years don’t ensure that equinoxes always fall on the same date.

This is why the Earth’s 23.5 degree tilt is all important in changing our seasons. Advancing 90 days, the Earth is at the autumnal equinox on or about September 21st. As the Earth revolves around the Sun, it gets positioned such that the Sun is directly over the equator.

The word equinox can also refer to the position of the sun at this moment. This can also be called the equinoctial point. The equinoxes are traditionally considered to mark the start of spring and fall.

At a deeper spiritual level, according to the Conscious Reminder Blog, the equinox is thought to represent: “the period of struggle between darkness and light, death and life. It occurs when the night and day will be equal, and the journey of the Sun to actually get there also signifies the journey of the Universe.

equal night

The equinox is defined as a day that occurs twice per year when the sun crosses the equator and the night and day are the same length. A day in March that is the beginning of spring and a day in September that is the beginning of fall, are examples of the equinox.

1 : either of the two points on the celestial sphere where the celestial equator intersects the ecliptic. 2 : either of the two times each year (as about March 21 and September 23) when the sun crosses the equator and day and night are everywhere on earth of approximately equal length.

12 hours

During the day in the Northern Hemisphere, the sun will rise to its maximum point at a southerly position, because it will go with the direction of the equator (south). In the Southern Hemisphere, the opposite occurs, as the sun rises to its maximum point in a northern direction.

Extending the Learning Remind students that the two reasons seasons occur are the tilt of a planet’s axis and its orbit around the sun.

The reasons for the Earth experiencing seasons are revolution, rotation, tilt, axial parallelism, and sphericity – yikes! and I thought it had only to do with the tilt of the Earth! Let’s first look at revolution, which is Earth’s orbit around the sun.

Seasons happen because Earth’s axis is tilted at an angle of about 23.4 degrees and different parts of Earth receive more solar energy than others.

• Earth’s orbit around the Sun is elliptical.
• Earth’s axis is the imaginary red line. timeanddate.com.
• Spring, summer, fall, and winter. ©iStockphoto.com/Smitt.

The Short Answer: Earth’s tilted axis causes the seasons. Throughout the year, different parts of Earth receive the Sun’s most direct rays. So, when the North Pole tilts toward the Sun, it’s summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it’s winter in the Northern Hemisphere.

Without tilt, there would be no summer season and no winter season. The equator would always be hot and the poles would always be cold. If you start at the equator and move north, the further north you go the colder it would get. When you found a temperature zone you liked, you could stop.

If you look at all four seasons across all of the Lower 48 states — for a grand total of 192 state-season combinations — there are only three instances of cooling. The Dakotas and Iowa are cooling ever so slightly in summer.

San Diego is the textbook example of beautiful year-round climate. It’s never too hot and never too cold, with a very minimal amount of that pesky California fog to get in the way—when it does roll in, it burns off pretty quickly in the morning. Winters average at 57° F, summers at 72° F—72° F, people!

Based on these criteria, California has the best weather of all 50 states. Coastal cities in south and central California, such as San Diego, Los Angeles, Long Beach, and Santa Barbara, experience only 20 inches of rain per year and temperatures typically between the low 60s and 85 degrees.

Most Humid States in the U.S.

• Alaska – 77.1%
• Florida – 74.5%
• Louisiana – 74.0%
• Mississippi – 73.6%
• Hawaii – 73.3%
• Iowa – 72.4%
• Michigan – 72.1%
• Indiana – 72.0%

The highest humidity ever recorded was a 95°F dew point in Saudi Arabia in 2003. In the United States, the most humid states are Alaska, Florida, Louisiana, Mississippi, and Hawaii. Sukkur, Pakistan, is located on the Indus River and is one of the most humid cities globally.

Nevada

To keep cool, humans shed excess heat through sweat, which evaporates into the air. High humidity prevents sweat from evaporating as readily, making humid heat more dangerous than dry heat.

Once the air gets above body temperature, things still get pretty miserable. 100+ degrees of dry heat makes any wind feel like you are standing in a hair dryer. The key to dry heat is just to hydrate and find shade.

Dry heat has temperarure of 33 degrees Celsius and relative humidity of 70%. We do not feel the very warm sensation because our perspiration can still leave our skin so we feel the cooling effect. Why is dry heat preferable to humid heat? Originally Answered: Why do most people tend to prefer dry heat over humid heat?

Experts generally agree that the ideal indoor humidity levels for comfort and for avoiding health effects are between 35 and 60 percent. When you’re spending time in a home or workplace with humidity levels in excess of 60 percent, it’s increasingly likely that you will experience certain health issues.