Play Thermometer Puzzle Online
Thermometer Puzzle is a shading logic game: fill a continuous stretch from each round bulb until every row and column matches its printed total. Thermometer Puzzle offers twenty original, unique-solution boards at an illustrated greenhouse table, with precise marking controls and explanations of each path. Play free online with no ads, account or download.
How to play Thermometer Puzzle online
- Read the totals outside each row and column and trace each thermometer from its round bulb.
- Use Fill for cells that must be shaded and Cross for cells that must stay empty. Follow the continuous-prefix rule around bends.
- Use Explain for local consequences, Check for direct conflicts and a hint when you need one proved cell.
- Match every total with continuous filled prefixes to complete the board and unlock the next level.
Controls
Choose Fill or Cross, then tap or click a cell to mark it. Tapping the same mark clears it. Clear removes the selected cell's mark, and Mark applies the active mode. Arrow keys select cells; Space or Enter marks, F selects Fill, X selects Cross, E explains, C checks, H hints and U undoes. Moving to another cell during a press cancels the tap.
A tip before you start
An empty cell cuts off every cell farther along the same thermometer. Trace that consequence through the bend before using a row total: excluding one late cell may be harmless, while excluding its bulb empties the whole path.
The bulb determines the filling order
Every cell belongs to one fixed thermometer. Its round bulb is the first cell, and the connected tube shows the order of later cells. You may fill none, some or all of that path, but you cannot leave a gap before a filled cell. A six-cell thermometer can therefore have a fill length from zero through six. A bend changes the drawing's direction without changing the order. Nothing rotates or moves between paths.
Read the outside numbers as cell totals
Each number above the board counts filled cells in that column; each number to the left counts filled cells in that row. These are totals, not lengths of separate runs. A zero line stays empty, while a line whose total equals its size fills completely. Other clues combine with the thermometer directions. All row totals, column totals and continuous prefixes must agree at the same time.
Follow consequences across a bend
Suppose a path visits three cells in one row before bending into the next. Filling its fourth cell also fills those first three cells, so the first row must have room for all three. If it has room for only two, the fourth cell and every later cell on that path must stay empty. Conversely, crossing the second cell prevents the third and fourth from filling even when they lie in different lines.
Twenty boards with increasing structural demands
The sequence grows from a four-by-four board with three thermometers to an eight-by-nine board with fifteen. Every next board contains more cells and a larger initial combination of possible fill lengths; the number of thermometers never decreases. All twenty boards were generated for this game and independently verified to have exactly one solution. The progression increases the amount of information to coordinate, while perceived difficulty can vary between players.
Explain, Check and exact hints do different jobs
Explain describes the selected cell's place in its path and the current row and column totals. Check highlights direct conflicts, such as too many filled cells or a filled cell after a crossed cell on the same thermometer. Finding no direct conflict does not prove that every current mark can finish. Hint searches the full prefix-and-total constraints and reveals one cell only when it proves a unique completion. An inconsistent position or a search limit makes no edit and costs no hint.
Crosses are useful, but optional at the finish
Cross marks record cells you have deduced must remain empty. You do not need to cross every empty cell to win: matching all totals with valid continuous fills is enough. Each board offers three hints. Undo restores the previous edit, including a hint edit, but does not refund a used hint. Restart asks before clearing the current attempt; it retains unlocked levels and best scores.
Play and keep progress on this device
Unlock the next puzzle by completing the current one. Local storage keeps unlocked levels, best scores and your sound preference where available. Reloading opens a fresh attempt while preserving those records. If storage is unavailable, progress lasts for that session. Help opens separately, Pause blocks input, and Full screen uses the browser's available full-screen controls.
Frequently asked questions
Can a thermometer be completely empty?
Yes. A fill length of zero is allowed, as are partial and full fills. The row and column totals determine which lengths fit.
Is this the same as Thermo Sudoku?
No. This Thermometer Puzzle shades cells and uses outside totals. It does not place digits or require Sudoku rows, columns or boxes.
Why does Check accept marks that Hint cannot finish?
Check looks for direct local conflicts. A position can satisfy those immediate checks yet fail when all paths and totals are considered together. Hint reports that contradiction without spending a hint.
Does a green clue mean the entire puzzle is correct?
It means the number of currently filled cells in that line matches its clue. Other lines and each thermometer's continuous fill must still agree.
Do hints or Undo affect my unlocked levels?
Only completing a puzzle unlocks the next level. Undo changes the board without refunding hints; restart and reload preserve locally saved unlocks and best scores.
About Thermometer Puzzle
Thermometer Puzzle is a shading logic game: fill a continuous stretch from each round bulb until every row and column matches its printed total. Thermometer Puzzle offers twenty original, unique-solution boards at an illustrated greenhouse table, with precise marking controls and explanations of each path. Play free online with no ads, account or download.
Play this puzzle / casual game in the embedded browser player. No app installation or MangoFun account is required. Follow the instructions shown inside the game; controls and device support depend on the title.
