air temp vs. surface temp

[Robyn@SYR]

Measuring both temps is important. Once you have a cage set up, they typically remain relative, unless you make a new change.

As you are finding, surface temps can be much different than air temps when the surface (substrate, basking spot) is directly affected by a heating or cooling element. If you are heating a hot spot or basking area with a light, heat tape or UTH, the surface temperature will reach a set temp. Just a quarter inch ABOVE that surface, the AIR temp may be 10 or 20 degrees LESS than the surface temp. And that is completely valid.

As the temps get higher, you see this more pronounced. In monitor lizard setups, we aim for 130F+ basking surface temps, yet the air temp just an inch higher may be 20-30F LOWER than that surface.

In a snake setup, if you are measuring temps with a digital thermo and probe (which measures air temp) and you find your hotspot to be 92F just a bit over the actual surface, the surface temp itself may indeed be 100+.

When setting the hot spot in a snake setup, a temp gun is definitely the right tool to use.

We use both temp guns and digital thermos in our facility, as they are complimentary tools. It is important to know both surface and air temps.

Tangent to that...

If your surface is NOT affected by direct heating or cooling, then the surface may very well be in equilibrium with the air temp. On the cool end of the cage, for example, substrate surface may indeed measure 75F with a temp gun, while the air temp two inches higher ALSO measures 75F.