Thetford is at its best in late spring and early summer, when the forest is at its greenest and the heathland flowers are in bloom. The Breckland landscape has a peculiar, continental-influenced microclimate — warmer and drier than most of Norfolk — which makes it pleasant for cycling and walking even in April.
Summer weekends see the most visitors in Thetford Forest, especially at the High Lodge visitor centre, which gets busy with families. Come on a weekday if you want the trails to yourself. Autumn brings colour to the forest and is an excellent time for wildlife — the deer rut happens in October, and the fallow deer at the edges of the forest are often visible from the cycling trails.
Winter is quiet and can be cold, but the forest has an austere beauty in frost. The days are short and the light fades quickly over the flat Breckland, but there are almost no other visitors, and the ruins feel particularly atmospheric.
The Thomas Paine Week, held in late January around Paine's birthday (29 January), brings lectures, walks, and events celebrating his legacy. The Thetford Forest Cycling Festival in the summer draws mountain bikers from across the region.