Spring (April–June) and autumn (September–October) are the best times to visit: mild weather, the abbey and other sites open, and the Borders landscape at its most atmospheric — green in spring, golden in autumn. Summer is busier, with the Border Abbeys tourist trail drawing visitors from Edinburgh and beyond.
The main local event is the Jedburgh Callant's Festival in late June or early July, a week of riding, music, and pageantry celebrating the Common Riding tradition — a Borders custom in which the town boundaries are ceremonially ridden on horseback. It is a genuine local celebration rather than a tourist event, and worth catching if your timing allows.
Winter is quiet but the abbeys and museums remain open, and the town is pleasant without the summer crowds.