September 2025: eclipse season meets gadget season
September 2025 was the tidy one. Thirty days, opening on a Monday and closing on a Tuesday, and both of those weekdays appeared five times. The month saved its best run for the final stretch. A phone went on sale on Friday 19 September. A partial solar eclipse followed on Sunday 21, and the equinox arrived at 18:19 UTC on Monday 22. Autumn was booked back to back, with no gaps.
Two eclipses, a fortnight apart
Eclipse season opened on Sunday 7 September, when a total lunar eclipse arrived. The full Harvest Moon, itself a supermoon, went dark for viewers from Europe all the way to Australia. A fortnight later, on Sunday 21 September, a partial solar eclipse passed over the Pacific and New Zealand. British watchers got the first and missed the second, which is the usual arrangement.
The moon ran to a Sunday timetable all month: full on the 7th, last quarter on the 14th, new on the 21st. Only the first quarter drifted, to Monday 29 September. Rarely does a month's moon line up in so neat a column of the grid.
The working month
September started flush with the beginning of ISO week 36 on Monday 1 September and closed on Tuesday 30 September. The tidiness bought 22 business days across weeks 36 to 40, with eight weekend days between them. Mondays and Tuesdays appeared five times each; every other weekday managed four. For rota writers, those five Mondays meant five clean week-starts to assign.
The month's ceremonies kept their dates. The Emmys went to a hospital ward and a studio backlot on Sunday 14 September. The Pitt took best drama; The Studio took best comedy.
The European Commission fined Google 2.95 billion euros on Friday 5 September, for the way it ran its advertising technology. The US Federal Reserve cut interest rates for the first time that year on Wednesday 17 September.
Phones, floods and a final release
Apple unveiled the iPhone 17 range on Tuesday 9 September, with iPhone Air, the ultra-thin one, as the headline. The handsets went on sale on Friday 19 September. The new phone landed two days before the solar eclipse and three before the equinox. No other month offered that run of appointments.
The month's worst weather arrived late. On Tuesday 23 September, Super Typhoon Ragasa hit Taiwan. A barrier lake overflowed in Hualien county, and the resulting floods left at least 17 people dead there. The storm continued on towards Hong Kong and the south China coast.
OpenAI closed the month with Sora 2, its video model, released on Tuesday 30 September. The month ended as it had begun, on a working day, with something new on a screen.
October 2025 arrived on a Wednesday with five Fridays in its pocket, but that is another month's arithmetic.