Surface temperature is not pool temperature

The best pool thermometers for 2026

A pool thermometer looks like the simplest object on this site and hides the one measurement error everyone makes: the top two centimetres of a pool in sun can be three or four degrees warmer than the water a swimmer is in. A floating thermometer with its sensor at the surface is measuring the film, not the pool, which is why the specification that matters first is the depth the sensor sits at — a weighted or hanging probe reads what the pool is actually at. The second is the accuracy, which classic analogue floats do not state and digital units often do, at ±0,5 or ±1 °C; for deciding whether a heat pump has done its job, half a degree is a genuine difference. Third is the form, which divides the shelf: a classic float with a liquid column that costs very little and lasts as long as nobody stands on it; a digital float with a display; and a wireless unit that sends to a base station or a phone, where the numbers to read are the range through water and air and the battery life, because a transmitter sitting in a pool is a battery you cannot easily reach. And the property none of them advertise: frost survival. A thermometer left in a pool over winter freezes into the ice, and the liquid-column types survive that far better than the electronics do. We compare sensor depth, accuracy, form, wireless range and battery, tether and frost behaviour.

These parts, one figure beside another

1. 

   Intex Poolthermometer 29039

   A floating white thermometer showing Celsius and Fahrenheit, supplied with a cord for tying it to the pool.

   Sensor depth

   Surface — it floats

   Accuracy

   Not published

   Form

   Floating, plastic, white. Temperature displayed in degrees Celsius or Fahrenheit

   Wireless range

   Not applicable — analogue

   Battery

   None required

   Tether

   A cord is included for fastening the thermometer to the pool

   Frost behaviour

   Not published

   Amazon reference

   B00I9LO0Z8 (one reference across 6 Amazon marketplaces)

   EAN

   0078257316793

   • A cord in the box, which four of the seven thermometers here publish
   • Both scales, which two listings in this family offer
   • No accuracy figure, like five of the seven here

   Best for: A frame pool where a reading to the nearest degree is all that is wanted

   Check price on Amazon
2. 

   AQUAVERITY Scoop Wasserthermometer

   A scoop-sample thermometer reading −20 to +50 °C at a published ±1 °C, with the method stated: thirty seconds submerged, then read at eye level.

   Sensor depth

   Wherever it is dipped — a scoop-sample instrument rather than a fixed float

   Accuracy

   ±1 °C, published. One of only two accuracy figures in this family

   Form

   Scoop sample thermometer, reading in Celsius and Fahrenheit, range −20 °C to +50 °C

   Wireless range

   Not applicable — analogue

   Battery

   None required

   Tether

   Not published

   Frost behaviour

   Not published as behaviour. The published range extends to −20 °C

   Amazon reference

   B0D1GSNV2N (one reference across 6 Amazon marketplaces)

   EAN

   5011405003270

   • Publishes an accuracy figure, which five thermometers in this family do not
   • Publishes the method: 30 seconds to stabilise, read at eye level
   • No tether, so it is carried to the water rather than left in it

   Best for: Cold-water swimming, an ice bath, or checking a spa before getting in

   Check price on Amazon
3. 

   Lantelme Poolthermometer sinkend

   The only thermometer on this shelf that deliberately sinks: it hangs on an 80 cm cord to read water below the surface, over a range of −15 to +60 °C.

   Sensor depth

   Below the surface — the thermometer sinks rather than floats, on a cord of about 80 cm. The only depth-reading instrument in this family

   Accuracy

   Not published

   Form

   Analogue, 20 × 3.4 × 0.8 cm, robust plastic housing, white. Range −15 °C to +60 °C

   Wireless range

   Not applicable — analogue, working without battery or power

   Battery

   None — stated to work without battery or power, immediately ready and low-maintenance

   Tether

   Fastening cord of about 80 cm, used to lower, fix and retrieve the thermometer

   Frost behaviour

   Not published as behaviour. The published range extends to −15 °C

   Amazon reference

   B00KISEWA8 (one reference across 6 Amazon marketplaces)

   EAN

   4260318929462

   • The only thermometer here that reads below the surface rather than on it
   • Publishes its own dimensions and its cord length — 20 cm and 80 cm
   • No accuracy figure, like five of the seven here

   Best for: A pool where the swimming water matters more than the sunlit surface film

   Check price on Amazon
4. 

   TFA Dostmann Schwimmbadthermometer 40.2005

   An analogue floating thermometer in stainless steel with a plastic fastening line, whose float ring holds it at the surface and which can be fixed at the pool edge.

   Sensor depth

   Surface — a float ring holds the thermometer at the water surface

   Accuracy

   Not published

   Form

   Analogue display with large figures, stainless steel body, blue. Float ring

   Wireless range

   Not applicable — analogue

   Battery

   None required

   Tether

   Plastic fastening line supplied, and the thermometer can be fixed at the pool edge

   Frost behaviour

   Not published

   Amazon reference

   DE B000EOQ9SY · US B000EOQ9SY · GB B005K71PX4 · FR B005K71PX4 · IT B000EOQ9SY · ES B000EOQ9SY

   EAN

   4009816013736

   • The only thermometer on this shelf built from stainless steel
   • Publishes large figures on the display, which is what an analogue pool thermometer is read at a distance
   • No accuracy figure and no temperature range published

   Best for: A pool where the thermometer stays in the water all season and is read from the terrace

   Check price on Amazon
5. 

   Mega Bloks Pool Thermometer DeLuxe

   A floating pool thermometer with a float ring. The listing publishes one bullet, and it gives the brand.

   Sensor depth

   Surface — a float ring is named in the title

   Accuracy

   Not published

   Form

   Floating, with a float ring. Nothing further published

   Wireless range

   Not published

   Battery

   Not published

   Tether

   Not published

   Frost behaviour

   Not published

   Amazon reference

   B00379IWZQ (one reference across 1 Amazon marketplace)

   EAN

   4019305269551

   • A float ring, which is what stops a thermometer standing on its end and being unreadable
   • A part number, which makes a replacement identifiable
   • One bullet, and it states the brand

   Best for: A buyer who wants a floating thermometer and will judge it on arrival

   Check price on Amazon
6. 

   Technoline WS 9079 radio thermometer

   A radio thermometer sending pool temperature to a base station up to 30 m away on 433.92 MHz, with an IP67 floating sender, min/max memory and battery indicators for both units.

   Sensor depth

   Surface — a floating pool sender

   Accuracy

   Not published

   Form

   Floating sender plus a base station showing pool temperature, indoor temperature and the time, with a stand and a wall hanging eye

   Wireless range

   433.92 MHz, up to 30 m in open ground

   Battery

   Batteries in both units, with separate low-battery indicators for base station and pool sender

   Tether

   Not published

   Frost behaviour

   Not published. Minimum and maximum values are recorded and cleared automatically at midnight

   Amazon reference

   B0F3JHLF3Z (one reference across 4 Amazon marketplaces)

   EAN

   4029665090795

   • Reads the pool from indoors, which is the whole point of a radio thermometer
   • Separate battery indicators for both units, so a dead sender is not mistaken for a cold pool
   • No accuracy figure, like five of the seven here

   Best for: A pool out of sight of the house, where the answer is wanted before walking out

   Check price on Amazon
7. 

   GoveeLife WLAN Poolthermometer P2

   The most precisely specified thermometer here: ±0.5 °C over −20 to +70 °C, IP68, a two-second refresh, up to 330 m through a gateway, and two years of exportable history.

   Sensor depth

   Surface — a floating sender

   Accuracy

   ±0.5 °C, published — the tightest figure in this family

   Form

   Floating WiFi thermometer with an H5044 gateway, 360-degree screen, supplied already paired. Range −20 °C to +70 °C, refresh every 2 seconds

   Wireless range

   Up to 330 m in open areas between sender and gateway; no distance limit through the app once the gateway is connected. 2.4 GHz networks only

   Battery

   Up to 500 days in standard mode and up to 3 years in extended mode, stated

   Tether

   Not published

   Frost behaviour

   Not published as behaviour. The published range extends to −20 °C

   Amazon reference

   B0GTQYQWTD (one reference across 4 Amazon marketplaces)

   EAN

   0810127739307

   • The tightest accuracy on this shelf — ±0.5 °C — and the widest range
   • Customisable alerts by gateway sound, email and app message
   • Requires a 2.4 GHz network and a gateway plugged in indoors

   Best for: A heated pool or spa where the temperature is worth watching continuously and recording

   Check price on Amazon