Sources and credits
Back to Autumn equinox on 23 September: why autumn in the Netherlands has two start dates
Sources for the editorially reviewed text. Occasion: on 22 September 2026, Hart van Nederland reported that the astronomical autumn began in the night to 23 September at 2.05 a.m. (https://www.hartvannederland.nl/weer/weerbericht/artikelen/astronomische-herfst-warm-droog-weer).
Sources
- KNMI – KNMI - Autumn (accessed 2026-09-24)
- U.S. Naval Observatory – https://aa.usno.navy.mil/api/seasons?year=2026 (accessed 2026-09-24)
- Hart van Nederland – Astronomical autumn begins: warm and dry weather continues | Hart van Nederland (accessed 2026-09-24)
- Met Office (UK) – Understanding equinoxes and solstices - Met Office (accessed 2026-09-24)
- U.S. Naval Observatory – https://aa.usno.navy.mil/api/rstt/oneday?date=2026-09-23&coords=52.10,5.18&tz=2 (accessed 2026-09-24)
- U.S. Naval Observatory – https://aa.usno.navy.mil/api/rstt/oneday?date=2026-09-26&coords=52.10,5.18&tz=2 (accessed 2026-09-24)
- MeteoSwiss (Swiss weather service) – Calendar, astronomical and meteorological seasons - MeteoSwiss (accessed 2026-09-24)
- NOAA National Centers for Environmental Information – Meteorological Versus Astronomical Seasons | News | National Centers for Environmental Information (NCEI) (accessed 2026-09-24)
Images
The Markermeer on a grey, windless day in early October 2014: flat water, a low islet with trees, a buoy and a long, low horizon.
Linus Follert · CC BY-SA 2.0 · Original source
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The 1919 sundial at De Eshof cemetery in Haren, photographed on 22 September 2010, around the start of the astronomical autumn.
Wutsje / Wikimedia Commons / CC-BY-SA 3.0 · CC BY-SA 3.0 · Original source
_Haren_Gn_NL.jpg){kind=link}
The earth seen from a geostationary satellite around the September equinox of 2010, at about six o’clock in the morning local time. The boundary between day and night then runs almost straight from north to south. Image by NASA Earth Observatory with data from EUMETSAT.
NASA Goddard Space Flight Center from Greenbelt, MD, USA · Public domain · Original source
_(6175313242).jpg){kind=link}
Validity
- Valid until 24 October 2026: the explanation belongs to the start of autumn 2026; after a month, the occasion has passed.
Article 7760979e581370b5835f7e84414d4726769a042d2d95d8f3ae77c2eb93acbf9b
Claims d8be89503d9a27da6adcf14350294117a67c4db3552dfb7308b9e8a350e50c34
Image a80b4e88a43776737ff762cd0937cbd5c9fbf5b81aa1f31561b03503f2714afa
Edition 2026-09-24