Parksville is at its best from July to mid-September, when the beach is warm enough to swim and the town is lively. July and August see the sand sculpting competition, and the ocean water peaks at around 20°C in midsummer — genuinely warm for the BC coast.
March and April are worth knowing about for wildlife: tens of thousands of Brant geese stop at Rathtrevor Beach on their northward migration, and the Brant Wildlife Festival in mid-April celebrates the spectacle with guided walks and events.
Spring and autumn are pleasant for hiking around Englishman River Falls and Cathedral Grove, which are much less crowded outside summer. Winter is quiet and rainy but mild by Canadian standards.