Winter and latitude, not longitude should of course guide the selection. Dublin today, Nov 30th, marks the start of the 6 week period where daylight is less than 8 hours, IMHO only wintertime (UTC) makes sense here. Oddly IST, Irish Standard Time and legal time, is UTC+0100. Sticking with IST all year round means 10:00 sunrise in late December for the north-western most parts of the country (Belmullet, for example).