# Mercuro: Thermometers Logic Puzzle

> A Thermometers logic puzzle game for iPhone and iPad. Fill each thermometer from the bulb so
> every row and column matches its number. 660 curated puzzles, three new daily puzzles, and no
> subscription.

- Website: https://www.arbazsiddiqui.me/app/mercuro/
- App Store: https://apps.apple.com/app/id6762402072
- Platforms: iPhone and iPad (iOS 17 or later). The App Store also lists Macs with Apple silicon and Apple Vision Pro.
- Price: free to play. Remove Ads $2.99 once. Mercuro Pro $4.99 once. No subscription.
- Made by: Arbaz Siddiqui, an independent developer (https://www.arbazsiddiqui.me/about)
- How it is built: https://www.arbazsiddiqui.me/mercuro
- Support: https://www.arbazsiddiqui.me/app/mercuro/support/
- Privacy policy: https://www.arbazsiddiqui.me/app/mercuro/privacy/
- Last updated: 2026-10-08

## Rules

1. The number beside each row or column says how many of its cells hold mercury.
2. Mercury starts at the bulb and rises without gaps.
3. A thermometer can be empty, full or filled partway.

Every board has exactly one solution, reachable by logic alone.

## Features

- **660 curated puzzles**: 330 free and 330 in Mercuro Pro, across 8 board sizes from 5x5 to 12x12. Free puzzles per size: 50 on 5x5, 6x6 and 7x7, 40 on 8x8 to 10x10, 30 on 11x11 and 12x12, in chapters of ten; solving 7 in a chapter opens the next.
- **Three daily puzzles**: Warm-Up, Daily and Challenge, the same for every player on the same date. The last two weeks stay in an archive.
- **Hints** that name the next forced move and explain why it follows.
- **Ads**: In the free game a full-screen ad plays every third puzzle you start, at most 12 a day. You get two free hints a day, and after that a hint, or a past day in the archive, costs a short optional ad. Either purchase removes all ads.
- **9 themes**: Glacier and Slate from the start; Coral, Plum, Matcha, Midnight, Porcelain, Forest and Riso Paper earned at 50 to 330 solves, or all unlocked with Pro.
- **Ranks**: eight, Novice to Virtuoso, each above Novice unlocking a theme; Virtuoso at 330 solves.
- **40 achievements** worth 1,000 Game Center points, and Game Center leaderboards for weekly solves, all-time solves and daily streak.
- **Offline play**: all puzzles are built into the app.

## Other Thermometers apps (US App Store, checked 2026-10-08)

| App | One-time purchases | Subscription | Puzzles |
|---|---|---|---|
| Mercuro | $2.99 Remove Ads, $4.99 Pro | None | 660 curated, 5x5 to 12x12 |
| Grids of Thermometers | $0.99 Remove Ads, $0.99 packs, $5.99 all packs | $4.49 Premium Subscription | Thousands of levels |
| Thermometers - Logic Puzzles | $3.99 remove-ads pack | $3.99 a month or $1.99 a week | 9,000+, 4x4 to 17x17 |
| Logic Puzzles - Thermometers | None listed | $0.49 a week, $1.39 a month or $13.90 a year | Thousands |

## Questions

**Is Mercuro free?** Yes. 330 puzzles and the three daily puzzles are free, supported by ads. Two optional one-time purchases remove ads ($2.99) or add 330 more puzzles with no ads ($4.99). There is no subscription.

**Where do ads appear?** In the free game a full-screen ad plays every third puzzle you start, at most 12 a day. You get two free hints a day, and after that a hint, or a past day in the archive, costs a short optional ad. Either purchase removes all of them.

**How do you play Thermometers?** Fill cells with mercury so each row and column has as many filled cells as its number. Mercury always starts at a thermometer’s bulb and rises without gaps.

**Do I ever have to guess?** No. Every board has exactly one solution, and you can reach it by logic alone.

**How many puzzles are there?** 660 curated puzzles: 330 free and 330 in Mercuro Pro, across eight board sizes from 5x5 to 12x12. Three new daily puzzles arrive every day on top of those.

**Does Mercuro work offline?** Yes. The puzzles, including the daily ones, are built into the app.

**Which devices does it run on?** iPhone and iPad with iOS 17 or later. The App Store also lists it for Macs with Apple silicon and for Apple Vision Pro.

**Is Mercuro on Android?** Not yet. Today it is on iPhone and iPad.

**Who makes Mercuro?** Arbaz Siddiqui, an independent developer. The project page explains how the solver, generator and hint engine are built.

## More about Mercuro

- [How to play Thermometers puzzles](https://www.arbazsiddiqui.me/app/mercuro/how-to-play-thermometers/)
- [Three new logic puzzles every day](https://www.arbazsiddiqui.me/app/mercuro/daily-logic-puzzle/)
- [A logic puzzle game with no subscription](https://www.arbazsiddiqui.me/app/mercuro/puzzle-game-no-subscription/)
- [Like Sudoku or nonograms? Try Thermometers](https://www.arbazsiddiqui.me/app/mercuro/games-like-sudoku-and-nonograms/)
- [A Grids of Thermometers alternative](https://www.arbazsiddiqui.me/app/mercuro/grids-of-thermometers-alternative/)
- [An alternative to Thermometers - Logic Puzzles](https://www.arbazsiddiqui.me/app/mercuro/thermometers-logic-puzzles-alternative/)