Christchurch sits on the Canterbury Plains at the edge of the Southern Alps, and the climate reflects that position. Summers are warm and generally sunny — December through March is the best time to visit, with January and February the warmest months (average highs around 22°C). The plains encourage dry, settled weather more often than the wetter West Coast gets, and clear Canterbury days can be spectacular. Watch out for the nor'west wind, which rolls hot and dry down from the Alps and can push temperatures above 30°C in the city.
Autumn (March to May) is pleasant and often has long stable spells, with deciduous trees in Hagley Park turning colour from April. Winter (June to August) is cool and sometimes frosty, with snowfall on the mountains visible from the city. The CBD is quieter in winter, which suits some visitors. Spring (September to November) warms gradually; the Botanic Gardens are at their best in October and November when the rose garden begins and the flowering trees peak.
The anniversary of the earthquake on 22 February draws quiet commemorations at the 185 Chairs memorial and other sites. If you are visiting around that date, be aware of the significance; it is not a festival, but it is a moment the city marks collectively.