Home
Weather Dublin
WeatherRadar
RainfallRadar
TemperatureRadar
WindRadar
LightningRadar
Weather News
Editor's Pick
Discover the app
Weather widget
Contact us
Apps
Home / Editor's Pick /

Meteorological vs astronomical autumn: which is it?

17:00
3 September 2025

Season start date
Meteorological vs astronomical autumn

© shutterstock / Volodymyr TVERDOKHLIB

You may be thinking that autumn doesn't start until later in September, and you wouldn't be wrong thinking this. There are two separate dates which can be used to define the start of the season.

Astronomically, the start of autumn takes places on the autumn equinox, when the length of day and night are the same in all parts of the world.

It is defined by the Earth's axis and orbit around the sun, and the exact date varies slightly each year.

This year, the autumn equinox falls on September 22nd at 07:19 pm BST, with the astronomical autumn running until December 21st.

Meteorologically, seasons are a fixed date because it is statistically easier to process the data by taking four equal quarters for each of the four seasons.

The meteorological autumn in the Northern Hemisphere is made up of September (starting on the 1st), October, November, with meteorological winter beginning on December 1st.

While the days are really getting shorter and cooler for us, the opposite is true for those in the Southern Hemisphere.

Learn more about our seasons in our weather explained video here:

What weather does autumn hold for us?read more
More on the topic
Wind map showing a powerful cyclone off the north-east coast of Australia. The red centre indicates a Category 5 storm near Cairns. The surrounding areas show strong wind patterns.
Thursday 19 March 2026

Gusts of up to 177 mph

Extreme cyclone heads to north Australia
Purple crocus flowers emerging from soil beside a garden path, with green grass and shrubs in the background.
Friday 20 March 2026

Astronomical spring

The spring equinox has passed
Split weather graphic showing a strong low-pressure system with swirling winds near the Azores on the left, and a radar map with showers and rain warning over the Canary Islands on the right.
Friday 20 March 2026

Storm Therese

Heavy rainfall on the Canary Islands
All weather news
This might also interest you
Split image showing strong winds over the UK on a forecast map and widespread rain and snow on a weather radar map.
Tuesday 27 January 2026

Severe gales & heavy rain

Storm Chandra makes impact
Split image showing aerial flooding in a town with muddy water covering roads on the left, and a rural road on the right blocked by heavy snowfall with vans stopped and a person walking in snow.
Tuesday 27 January 2026

Storm Chandra

Flooding, gales, and heavy snow
Split image showing a person in a yellow jacket struggling against strong winds and heavy rain on a street at night on the left, and an Irish wind forecast map on the right with red and purple shading, gusts up to 75 mph, and a wind warning icon, divided by a curved white line.
Saturday 24 January 2026

On this day...

Historic Storm Éowyn arrives
All articles
Weather & Radar

Weather & Radar is also available on

Google Play StoreApp Store

Company

Contact us Privacy Policy Legal info Accessibility statement

Services

Uploader

Socials

facebooktwitteryouTubelinkList