The dates of the most recent UK General Elections were:
- Thu 4 Jul 2024
- Thu 12 Dec 2019
- Thu 8 Jun 2017
- Thu 7 May 2015
- Thu 6 May 2010
- Thu 5 May 2005
- Thu 7 Jun 2001
- Thu 1 May 1997
- Thu 9 Apr 1992
- Thu 11 Jun 1987
- Thu 9 Jun 1983
- Thu 3 May 1979
- Thu 10 Oct 1974
- Thu 28 Feb 1974
- Thu 18 Jun 1970
- Thu 31 Mar 1966
It is clear that a summer day --- when it is daylight for many hours --- is preferred. We also see that, from Oct 1974 onwards, the dates are near the beginning of a month. We have to go all the way back to Feb 1974 to see a date later than the 12th of any month. This is true no matter the party of the Prime Minister choosing the date, and no matter which party is expected to win.
Granted, the timing of the 2015 General Election accorded with the Fixed-term Parliaments Act 2011. Per this Act, General Elections are "automatically scheduled for the first Thursday in May of the fifth year after the previous general election, or the fourth year if the date of the previous election was before the first Thursday in May" [Wiki]. But then the 2017 and 2019 General Elections were called early, so the aforementioned default date doesn't explain the actual dates chosen. And that Act was repealed in 2022 anyway.
Question: Why do UK Prime Ministers choose a day near the beginning of a month for a General Election?
This is not about the convention to choose a Thursday, a convention very rarely broken.