Cookstown and the surrounding countryside can be visited year-round, but the practical window for getting the most out of the area runs from April to October. The ancient sites — Beaghmore Stone Circles, Ardboe High Cross, Tullyhogue Fort — are always accessible and free to visit, but the bogland setting of Beaghmore is particularly atmospheric in fine weather when the Sperrins are clear. Wellbrook Beetling Mill, the National Trust property, operates on a seasonal schedule and closes over winter.
Summer brings the longest days and the best chance of clear weather, though the Sperrins are frequently cloudy and the area receives steady Atlantic rainfall throughout the year. June and July are the driest months on average. August is the busiest month for visitors in Northern Ireland generally, but even then Cookstown's sites are far from crowded — this is well off the main tourist route.
Spring and early autumn are often the best times to visit: lighter traffic, lower accommodation prices, and the countryside at its most photogenic. The bogland around Beaghmore is particularly good in October when the heather and grasses are coloured. Winter is quiet and can be grey, but the sites are unchanged and the town's cafes and pubs are welcoming.