Start from the White Horse camping area about 2 kms north of Mount Cook village.
Weather can change rapidly - check for info at the Mount Cook Visitor Centre before you set out.
Hooker Lake can be reached all year round in about an hour's walk from the White Horse Hill camping ground. The Hooker Valley Track is well indicated and ends at a viewpoint by the lake. You can easily descend from there to the edge of the lake if you wish.