A frog that dries out as the room heats up
A green tree frog takes in water and air partly through its skin, so the species experiences a heatwave as a drying event before it experiences it as a temperature event. Hot air pulls moisture from the enclosure's plants, substrate and the frog itself, and a green tree frog that cannot stay moist cannot regulate anything else either. Move the enclosure to the coolest, darkest room you have; darkness suits this nocturnal frog and usually coincides with the rooms that heat slowest. Cover part of the mesh lid with a clean damp cloth so humidity lingers, while leaving a section open so the air does not stagnate. The frog should spend the worst hours tucked against damp foliage or sitting in its water, which is exactly where it will put itself if you keep those options wet.
Treated water, topped up and misted often
Every drop of water that touches a green tree frog in a heatwave should be dechlorinated, because heat-stressed skin absorbs what is in the water more readily and chlorine is a harm this species never has to face. Keep the soaking bowl full and change it daily at minimum, since warm standing water grows bacteria quickly and a frog sits in its bowl for long stretches. Mist the enclosure walls, leaves and the frog's favourite perches with treated water whenever surfaces look dry, which in a heatwave may be several times a day. A green tree frog that parks itself in the bowl for hours is behaving sensibly, not strangely; your job is making sure the water it parks in stays clean enough to help rather than harm.
Hands entirely off a hot frog
Of all the animals in this heatwave, the green tree frog is the one handling helps least. Human skin carries salts and oils that a frog's permeable skin takes up directly, and a hot, stressed frog has no reserves for a chase around its enclosure. All heatwave care for this species is done around the animal: misting past it, changing water beside it, shading the glass in front of it. Feeding can wait for the cooler night or even the night after; a green tree frog that is too warm will not chase insects, and loose feeders in a hot enclosure are a nuisance to a frog that wants only to sit still. Brief visual checks by low light tell you everything handling would, without costing the frog anything.
Signs the frog is beyond coping
A green tree frog managing the heat stays moist-skinned, perches or soaks in its usual spots, and rouses at night when the room cools. Worry about a frog whose skin looks dry or dull despite misting, one slumped on the floor rather than climbing, or one that fails to react when its perch is gently shifted. A frog found floating listlessly or lying out of the water in full view at midday is also telling you the enclosure's conditions have beaten it. Deepen the cooling, refresh the water, and seek a reptile vet's advice the same day for those signs, warming or cooling the frog only gradually in the meantime, because amphibians shock easily under sudden change.
Misting rounds shared across the household
The green tree frog's heatwave survival is a timetable of small acts: misting before work, misting at midday, a water change, another misting in the evening peak. Miss two rounds in a row and the enclosure dries past what the frog can fix by soaking. KinsLe's Care Teams lets you turn that timetable into assigned duties for the frog, each round marked complete with a timestamp, so whoever is home at each hour knows their misting is the load-bearing one and the frog's humidity holds steady all day.