About Revisions Grand Lake Town of Grand Lake, Grand Lake, CO Max Depth: Over 150ft/46m Average Viz: 16-20ft/5-6m Entry Type: Shore Bottom Composition: Sand/Rock Aquatic Life: Might See Something Spring: Under 50°F/10°C Summer: 50-55°F/10-13°C Fall: 50-55°F/10-13°C Winter: Under 50°F/10°C 8/14/2008 3:20 PM

Deep natural lake in Colorado offers challenging high altitude diving.


At 8400 feet above sea level, and being a natural deep lake (285 feet deep) visibility can often be up to 25 feet during July.


June is often poor visibility due to the lake having recently "turned", and Augusts algae layer grows to 20 feet deep, blotting out much available light at 50 feet in depth.


Temps at 60 feet are 42-46 degrees fahrenheit.


In late August, the lake will "turn" again, reducing visibility to around 6-8 feet.


There is a picnic area and outhouse by the East Portal. The Marina offers a boat ramp and restrooms. You can also rent small recreational boats there.

There is a wall to dive at the East Portal, about 100 yards off shore. There’s a nice sand slope if you are diving off of the marina. Night dives only at the marina. There you can find objects including bottles and engines.


Very noticeable thermocline around 30 feet. Temperature change of 15-20 degrees.