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
Split image: Low water levels in a river and a map of Europe showing temperature anomalies in red. March was too warm and too dry in many places. The greatest anomalies were observed in Eastern Europe.
Wednesday 15 April 2026

Almost a new record

March: Second warmest across Europe
Side-by-side weather maps of Ireland showing bands of rain and scattered thunderstorms, with lightning icon highlighting storm activity and blue rain areas moving across the country.
Wednesday 15 April 2026

Lightning on the radar

Thundery showers move through Ireland
Weather map of the USA showing a band of heavy rain and numerous thunderstorms over the Great Lakes. The warning symbol indicates severe weather conditions.
Tuesday 14 April 2026

Tornado warning

Thunderstorm front in the northern US
All weather news
This might also interest you
Split weather map showing UK wind speeds in orange-red shades up to 40 mph on the left and warning levels in green-yellow on the right, with a central wind warning sign.
Wednesday 22 October 2025

Warnings active

Storm Benjamin impacts the UK
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 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
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