Terrace has a maritime-influenced climate softened by the Coast Mountains: cool wet winters and short warm summers. Snow falls heavily from November through March but rarely accumulates much in the city itself — the snow stays in the mountains, where it feeds Shames Mountain's famous depth.
Summer (June to August) is the obvious season — long days, swimming at Lakelse Lake, and the main salmon runs on the Skeena. Daytime temperatures sit in the low twenties Celsius, occasionally pushing thirty.
Autumn (September to early November) is the best window if you've come to fish or to see the country at its most dramatic — the cottonwoods turn yellow, the rivers are still running, and the steelhead are in. Bring waterproofs; it rains a lot.
Winter (December to March) is for skiers. The town empties out, the days are short, but the Shames snowpack is unmatched.
Avoid mid-October if you can — it tends to be the wettest stretch of the year, and the salmon runs are starting to wind down.