Around 2,500 feet…probabaly around May, even then some middle upland lakes might be fishable in April, but the water will be cold. Generally, I don’t start looking above 3,000 feet ’till after June, but have gone into high lakes and had fair fishing in June, those haven’t been above 3,500 feet however. And that of course all has to do with the lake exposure and how much snow has occured on a given year.
McPil