(This post is part of the Genuinely Approachable Sudoku (GAS) series.)
Numeral diffusion occurs gradually in this Slow Thermo-Sudoku.

PDF

or solve online (using SudokuPad)

Theme: Thermodynamic Disequilibrium

Author/Opus: This is the 134th puzzle from Philip Newman, part of the Genuinely Approachable Sudoku (GAS) team.

Rules: Standard Sudoku rules (insert a number from 1 to 9 into each cell so that no number repeats in any row, column, or bold region). Some thermometer shapes are in the grid; numbers must either increase or stay the same in each cell going from the round bulb to the flat end. (For instance, a thermometer might contain the sequence 233577888 in that order.)

GAS Time Standards (highlight to view): Two party hats (🎩🥳): 5:00; One party hat (🥳): 12:00. All other solvers earn a 🦕: Yuppie Yunmenglong.

Thomas Hits the GAS (highlight to view): 1:29, with SudokuPad replay file shared as a download for now (requires loading via settings menu with improvements expected before people should use this regularly).

Solution: PDF; solving video with explanation to be added later from GAS team.

Note: Follow this link for more Thermo-Sudoku puzzles. If you are new to this puzzle type, here are our easiest Thermo-Sudoku to get started on. More Thermo-Sudoku puzzles can be found in these books in our e-store. Also, visit this page to purchase all of the puzzles from the 16th World Sudoku Championship including some Thermo-Sudoku.

Note 2: Comments on the blog are great! For a more interactive discussion, please also consider using our Daily GAS discussion post on the GMPuzzles Discord. Not a member of the Discord? Click this link for basic access.