Gem Mary Lake Water Temperature
Gem Mary Lake in Orange County, Florida typically sits around 88°F at the surface in September — warmest in Sep (~88°F) and coldest in Dec (~71°F). That is a typical value for the month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 25 field readings (2010–2025) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Gem Mary Lake warm enough to swim?
Very comfortable for swimming. Warm surface water can also favor blue-green algae in nutrient-rich lakes, so check for advisories before you go in.
Want more than temperature? Gem Mary Lake water quality: clarity, algae, phosphorus, depth, fish species, and current advisories, all on one page.
Water temperatures at nearby Florida lakes
Summer average ~83°F
Summer average ~88°F
Summer average ~86°F
Summer average ~87°F
Summer average ~85°F
Summer average ~86°F
Explore water temperatures
Where to stay near Gem Mary Lake
Planning a swim or lake trip? Compare cabins, lodges, and vacation rentals near Gem Mary Lake — live availability and prices. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Gem Mary Lake
Prices for Sep 18–20, 4 adults. Change dates on the map below.
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Frequently asked questions
What is the water temperature of Gem Mary Lake?
Gem Mary Lake typically sits around 88°F at the surface in September, from 25 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
When is Gem Mary Lake warmest?
Surface water at Gem Mary Lake is typically warmest in September, reaching about 88°F. Lake surface temperature lags air temperature by several weeks, so the warmest water usually arrives in mid-to-late summer even though the hottest air can come earlier.
Is Gem Mary Lake warm enough to swim?
At its typical summer peak of about 87°F, Gem Mary Lake rates as "warm" for swimming. Very comfortable for swimming. Warm surface water can also favor blue-green algae in nutrient-rich lakes, so check for advisories before you go in.
Where does this Gem Mary Lake water temperature data come from?
Every temperature on this page is a typical (climatological) value computed from real surface-water field readings collected by state and federal agencies and published through the EPA Water Quality Portal — 25 readings from 1 monitoring station between 2010 and 2025. They describe what is typical for each month, not the temperature right now.
About this data
Water temperatures are a climatology — the typical value for each month, averaged from real surface-water field readings collected by state and federal agencies and published through the EPA Water Quality Portal. They tell you what to expect, not the temperature at this moment. Actual conditions vary with recent weather, depth, and time of day.