TempPro TempAir Solar Pool Thermometer Floating with Waterproof Sensor

On a small yard the tank is often thirty steps from the back door, and a thermometer you have to walk out to read is a reason to stay in. The TempAir Solar is a white float with a blue band, a small solar panel and a little LCD on top; it sends the reading to an indoor receiver with big backlit digits that stands on a counter. The listing gives ±0.9 °F (±0.5 °C) between 32 and 140 °F, a sensor range of -40 to 158 °F, 5-second updates and an IPX8 rating.

The sensor charges itself from the sun into a built-in battery, and the receiver runs on two included AAA cells. The 500 ft range is the maker’s figure; the real one depends on the walls in between. It does not keep time, so the clock for the plunge is still a separate thing.

Tip: Tie the float at the opposite end from the chiller’s return hose, so the receiver shows the tank and not the stream of freshly chilled water.