So, When Does Autumn Begin? 

Many people love autumn and are excited about it (not me, I hate autumn!) ,which leaves a lot of people asking themselves, “When Does Autumn Begin”? You might notice the air gets cooler and leaves start changing colour. Yet, it’s tricky to pin down the exact day autumn starts. There’s been plenty of warm September’s that feel like summer! Autumn begins in September in the Northern Hemisphere and in March in the Southern Hemisphere.

So let’s look into how different systems decide the first day of autumn.

Autumnal Equinox

The Autumnal Equinox marks the start of autumn, when day and night are nearly equal in length. This phenomenon occurs due to the Earth’s axial tilt, positioning the equator directly under the sun.

Dates for Northern and Southern Hemispheres

Autumn marks a significant time of year in both the Northern and Southern Hemispheres. The equinox heralds its arrival. Here are the crucial dates for these regions.

Hemisphere	Autumn Equinox Date and Time
Northern	22 September 2024 at 14:43 CEST (12:43 UTC)
Southern	20 March 2025 at 10:01 CET (09:01 UTC)

Equinoxes mark a period when day and night are of almost equal length. Yet, they don’t bring exactly 12 hours of daylight and 12 hours of darkness. This variation arises because of how sunrise and sunset times change.

In 2023, for instance, the Northern Hemisphere saw autumn begin on 23 September, at 07:49 AM (BST). This discrepancy in equinox times is due to the measurement focusing on the sun’s centre, not its edge. As such, equinox dates can range from 22 to 24 September.

Understanding these dates and times helps us welcome the season more accurately.

Astronomical vs. Meteorological Autumn

Astronomical autumn is determined by the position of Earth’s axis and lasts for about 89 days, whereas meteorological autumn is based on temperature cycles and begins at different dates in various places.

Definitions and Differences

Astronomical seasons depend on Earth’s position relative to the sun. This system considers events like equinoxes and solstices to mark the beginning and end of seasons. For instance, astronomical autumn starts between 22 or 23 September and wraps up on 21 or 22 December in the Gregorian calendar.

Leap years can cause slight changes in these dates.

Meteorological seasons, however, follow the annual temperature cycle and are split into full months based on the meteorological system. Meteorological autumn aligns with cooler temperatures from 1 September to 30 November every year.

These dates stay consistent, making weather forecasting more straightforward for entities like the Met Office. Unlike astronomical seasons, this method does not adjust for leap years since it relies on average monthly temperatures rather than direct sunlight positions or Earth’s tilt degrees.

Cultural and Historical Significance of Autumn

Many cultures worldwide have unique traditions and celebrations to mark the arrival of autumn. One such example is the Mid-Autumn Festival, celebrated in several East Asian countries with lighting paper lanterns and enjoying mooncakes together.

Traditions and Celebrations Globally

Autumn brings a mix of vibrant traditions and celebrations all around the world. Each marks the changing of seasons in unique ways.

1. Mabon, known as the second harvest, honours the approaching winter. People gather to celebrate the plentiful harvest that autumn brings. They share food that they have grown and prepare for the colder months ahead.
2. Michaelmas, mainly celebrated in the Catholic Church, falls at the end of September. This day honours Saint Michael, with feasts and gatherings that bring communities together.
3. Higan is a time to honour ancestors in several East Asian cultures. Families visit graves, cleaning them and offering prayers and food items during this period around the autumnal equinox.
4. The Mid-Autumn Festival celebrates the summer’s bounty and is famous for its mooncakes and lanterns. Family members come together on this night when the moon is fullest to give thanks for their harvest.
5. Navaratri, occurring in September or October, spans nine nights and is filled with dance, music, and prayers across different parts of India. It’s a vibrant festival dedicated to Hindu deities and symbolises good over evil.

These varied celebrations highlight how different cultures cherish the arrival of autumn in their calendars through ancient myths, religious festivals, and customs tied deeply to nature’s cycles.

The Start Of Autumn

The start of the autumnal period varies globally. Those in northern territories acknowledge it in September, while those in southern territories do in March. This discrepancy arises due to our planet’s leaning and orbiting around the sun, altering our seasons.

We recognise two forms of autumn: one influenced by astral configurations, and the other by weather patterns. Each presents distinct methods to denote the cessation of summer and the commencement of cooler months.

This year, Autumn starts Sunday, 22 Sept 2024, 1:43 pm in the UK.

FAQs

1. When does autumn officially start according to the astronomical calendar?

Autumn begins with the September equinox, which is when day and night are of equal length due to the tilt of the Earth’s rotational axis. The exact date can vary in different places due to time differences.

2. How does meteorological calendar define the beginning of autumn?

The meteorological calendar defines the start of autumn based on monthly statistics such as average temperature and hours of sunshine, marking it on a set date for consistency.

3. What events mark the transition from summer to autumn?

Several traditions and astronomical events mark this transition, including the harvest moon, full moon festival, pagan rituals and the tradition of higan. These coincide with shorter daylight hours and dark evenings symbolising the end of summer.

4. How do we know when winter is coming after autumn starts?

As we move into the fall season or ‘libra season’, there are phenological indicators like changing leaves colour or strong winds that signal the coming winter months, along with a decrease in daylight hours leading up to the shortest day of the year – winter solstice.

5. Does everyone experience the start of fall at the same time across United Kingdom?

No! The first official day of Autumn may be observed on different days across the British Isles owing to local issues like geographical position affecting Royal Observatory Greenwich Mean Time (GMT), Earth’s atmospheric conditions or eventhe closest part position relative to sun rise points.

6. Are there any community activities related during Autumn season?

Yes! Many communities in UK celebrate change in seasons by organising local festivals around equinoxes or engage in activities like viewing Northern Lights; making it a valuable part their culture.