One of the definitions of timezone being correct for a location, is that the average Sun is due south at local noon on the clock. This means that there’s about the same length of time from sunrise to 12:00, as there is the length of time between 12:00 and sunset.
In historical times, the local church would ring the bells based on the local time, such that at 12:00 the Sun would due south. Of course, due to different places being at different longitudes, the Sun would be due south at different absolute times. There’s 4 minutes difference for each degree of longitude difference in the timing of the Sun being due south.
This caused some problems when the railways allowed relatively fast travel east and west as each location had been operating on its own time. There were some issues with timetabling and advertising the arrival and departure timings of trains as a result of those differences. It was then decided that the railways would operate on a time frame that was consistent for the train company such that when the train company clock said it was 9:00 in Paris, it was also 9am in Brest. Previously it would have been 8.32 in Brest as it’s 7 degrees further west than Paris. Each location with a railway station then started to use the railway clock as their local standard, and the countries started to operate on a consistent time zone.
The advent of telegraphy and radio was another pressure on places to have a consistent time that was the same set of numbers on the clocks in each location. It became easier to have time signals that would allow easier synchronisation of clocks.
Then, in the 20th century, it was agreed to standardise timezones across the world, with Greenwich in London to be the zero point. As Greenwich was defined to be the zero meridian of longitude, this meant that there were 24 time zones of an hour difference around the world, each separated from the next by 15 degrees of longitude. Once passing 7.5 degrees east or west from the center line of a timezone, it was at that point that the next timezone was due to start.
Of course there were some political and social considerations in play now, as it was not really useful to have a country split into multiple timezones. Portions of Ireland are far enough west that they should be in the GMT-1 zone, but it was decided to put all of Ireland into the GMT zone. France and Germany decided to work in the GMT+1 zone, even though Paris is close to the center of the GMT zone.
That’s a little bit on the history of timezones.
The current status quo is that Ireland is set in the GMT timezone, and we change to GMT+1 from approximately Spring equinox to the Autumn equinox. This means that in Dublin on July 1st, the sun is due south at 13:30. In Killarney on the same day the sun is due south at 13.43.
There’s a decision that has been made to stop the annual change of the clocks for DST, and that change is to be welcomed. The change has been seen to cause health issues due to the enforced body clock changes with changes in sleep patterns, and there’s also a well-proven uptick in accidents also mainly due to the sleep pattern changes forced onto people around the clock change.
One argument that continually gets put out there for DST is that it’s safer for the children at school, that they travel when it’s brighter or get more time in the light after school. It would be a much better change to change the start time of school to suit, instead of forcing a clock change on everyone.
I would suggest that Ireland go to GMT ans stay on GMT year-round Any businesses that operate with European groups can change their start and end times to suit the Eurpean office timings, e.g. starting at 7am and finishing at 4pm. It would be the same effect on our bodies as if we were GMT+1 and working between 8 and 5 in that timezone. The agricultural sector follows the solar day anyway, so the listed numbers on the clock are of no relevance to a cow’s desired milking time.
To recap: Ireland should go to GMT, and stay on GMT. Schools should be able to change their start times to suit the light conditions, if the lighting conditions are considered to be a timing requirement. Business should have the office openings as appropriate for their business. Doing all of this ensures that our clocks are correct as per the Sun.