01Winter is the design case
Anything sold on southern performance figures will disappoint here. What matters in a Canadian winter is short December days, low sun angle, snow sitting on the panel, and cold battery chemistry. Fixtures should be specified for the worst month at your latitude, not the average one.
02Mounting angle earns its keep
A panel tilted steeply sheds snow and catches a low winter sun. A flat-mounted panel does neither. On a solar fixture the bracket is a performance component, not a bracket.
03Sensor behaviour
Dusk-to-dawn, motion-triggered, or dimmed-then-boosted all draw very differently from the same battery. Decide how the light should behave before deciding how big it needs to be.
04Sealing rating
Outdoor fixtures here see driven snow, meltwater and a wide temperature swing in a single day. The ingress rating on the housing is worth reading rather than assuming.