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Stick-on window thermometer: what to check before you buy

Updated: October 2026

A stick-on window thermometer is a small gauge on the outside of the pane so you can read the outdoor side from indoors before you pick a coat. In the six amazon.co.uk listings compared here, the dials sit between about £4.31 and about £6.49, and the only digital, the Youshiko YC779, is about £18.99. The Products Compared editorial team used those listings and public UK sources on 15 October 2026. There was no laboratory test. If you buy through our Amazon links, we may earn a commission at no extra cost to you. The [window thermometer comparison](/hub/climate-measuring/window-thermometer) holds the six-row table.

A stick-on window thermometer is a small gauge on the outside of the pane so you can read the outdoor side from indoors before you pick a coat.

Our top picks

Faithfull Faithfull stick-on window thermometer

Best overall

Faithfull Faithfull stick-on window thermometer
7.2/10about £4.31
View offer
Brannan Brannan outside window thermometer

Rank 2

Brannan Brannan outside window thermometer
7.6/10about £5.95
View offer
Youshiko Youshiko YC779 digital window thermometer

Alternative

Youshiko Youshiko YC779 digital window thermometer
5.7/10about £18.99
View offer
On this page
  1. 1.What a stick-on window thermometer is for
  2. 2.Dial, multipack, or digital
  3. 3.Accuracy lines you can actually cite
  4. 4.When to buy something else
  5. 5.Which kind to buy

What a stick-on window thermometer is for

The job is a glance from the kitchen or a flat, without opening the window. The Faithfull, the Brannan, and the multipacks put a case on the glass and a scale you can see from the room. It is the wrong tool for a greenhouse, for humidity, or for a phone alert. The Royal Horticultural Society puts a maximum-and-minimum thermometer near the plants, and it treats damage as typical once heat builds above 27 °C. The Met Office measures air temperature in a Stevenson screen at 1.25 m, not on a window. Where to move a high reading is on the sun and shade page.

Dial, multipack, or digital

A named single dial is the Faithfull FAITHWINDOW at about £4.31, with 3.9 from 684 ratings, or the Brannan 14/419/3 at about £5.95, with 3.7 from 153. The Faithfull listing still says the display is digital and the power source is AC. UK reviews describe a dial with a lever. Keep both facts. A multipack covers a second window or a caravan if you accept a thinner record. The Jiujuda9 four-pack is about £5.99, 4.3 from 25 UK ratings. The SYNKIGY two-pack is about £6.49, with a bullet range of 0 °C to 50 °C and no review line. The best window thermometer page splits those packs by job. The digital is the Youshiko YC779 at about £18.99, with minimum and maximum and one AAA that is not included.
Faithfull Faithfull stick-on window thermometer

Testsieger

Faithfull Faithfull stick-on window thermometer
7.2/10about £4.31
View offer

Accuracy lines you can actually cite

A printed scale is not a tolerance. The line you can cite is the Brannan data sheet for model 14/419/3: −20 °C to +50 °C, divisions of 1 °C, and ±2.0 °C at ambient, on a case made in the United Kingdom. Brannan's own site lists that model at £5.82 including VAT. This amazon.co.uk row is about £5.95, and its fields still say an upper rating of 120 °F and power ac. Use the sheet for the tolerance and the dump for the Amazon price. The Faithfull maker page does not state ±2 °C. SYNKIGY says 0 °C to 50 °C, so a frost morning is off the scale.

When to buy something else

Buy a greenhouse maximum-and-minimum, and hang it among the plants, when you are managing heat in a glasshouse. None of the six stick-ons is that instrument. The Youshiko stores a high and a low, but it is still a sensor on a window. Buy a hygrometer when you need humidity. A north-facing window in shade is still not a Stevenson screen. If you need the official air temperature, use the Met Office, not a dial at about £5.

Which kind to buy

If you can see a shaded pane from indoors, a dial in this set is the coat check. The Faithfull is the long UK review file at about £4.31. The Brannan is the model with ±2.0 °C at ambient. The Youshiko is the buy only when last night's low on that glass is the point.

Common questions

Do these window thermometers need a battery?
The mechanical dials in this set do not, on the evidence in the file. UK reviews of the Faithfull do not mention a cell, and the Brannan sheet describes a bimetal hairspring with no cell. The Youshiko YC779 needs one 1.5 V AAA, and the cell is not included. The Whispern Cloud listing does not answer a customer question about batteries.
Are stick-on window thermometers mercury?
The six listings kept here are plastic dials or a battery LCD, not mercury columns. Faithfull's maker page says the FAITHWINDOW is mercury free. GOV.UK guidance restricts mercury thermometers on the Great Britain market unless an exemption applies. An old broken mercury thermometer is hazardous waste, and you do not vacuum the droplets.
Why do some Amazon listings say digital when the picture is a dial?
The attribute table and the object in the box are sometimes different. On the Faithfull, the table says display type Digital and power AC, while UK reviews describe a dial with a lever, and those reviews do not mention a cell. The Whispern Cloud row says Digital in the attribute and analogue in the bullets. Treat digital as a claim to check.
Is about £19 for a digital worth it for a coat check?
Not in this set. The Youshiko is about £18.99 and is the only listing that shows minimum and maximum. A coat check is the current number on a shaded pane, which the Faithfull at about £4.31 and the Brannan at about £5.95 are sold to do, without a cell. Buy the digital when last night's low on that glass is the point.
What if a unit arrives stuck on one number?
The Consumer Rights Act 2015, section 22, sets a short-term right to reject that ordinarily lasts 30 days. A window thermometer that never moves, such as a Youshiko review that stayed at 50 °C, is the sort of fault that right is for. A reading that climbs only in direct sun is a siting limit. Say which of the two you have before you open a return.

Related pages

Digital or analogue window thermometer

Window thermometer

Best window thermometer UK, one listing for each job

How to stick a thermometer on outside window glass

Window thermometer inaccurate: sun, shade, and noon

Sources

Public UK sources used for this comparison. Listing prices, stars, and review counts are the amazon.co.uk dump dated 15 October 2026.

  1. Met Office — how we measure temperature (retrieved 15 October 2026)
  2. Met Office — make your own thermometer box (retrieved 15 October 2026)
  3. GOV.UK — controls on mercury-added products (retrieved 15 October 2026)
  4. Consumer Rights Act 2015, section 22 (retrieved 15 October 2026)
  5. Brannan data sheet 14/419/3 (retrieved 15 October 2026)
  6. Brannan — dial window thermometer (retrieved 15 October 2026)
  7. RHS — heating greenhouses efficiently (retrieved 15 October 2026)
  8. Thermometer World — dial window thermometer (retrieved 15 October 2026)