celsius

Terminal weather as a first-person sky view. You look up into the sky you would see right now at your location, drawn in truecolor half-blocks directly in your terminal. Clouds drift, the sun tracks its altitude, stars fade in at twilight, rain slants with the wind, and thunderstorms flash.

Install

# prebuilt binary, no Rust toolchain needed
curl -fsSL https://raw.githubusercontent.com/lmarkmann/celsius/main/install.sh | sh
# or
brew install lmarkmann/tap/celsius
# or, prebuilt binary, v0.2.0+
cargo binstall -y celsius
# or, from source
cargo install celsius

The script needs curl or wget, verifies the SHA-256 published with the release, and installs into $XDG_BIN_HOME, or ~/.local/bin if that is unset. Options go after -s --, so | sh -s -- --install-dir ~/bin or | sh -s -- --version v0.5.0. It covers arm64 macOS and x86_64 Linux. Intel Mac and ARM Linux have no prebuilt binary, so Homebrew and cargo install build from source there. Windows has a prebuilt binary but no installer: take the x86_64-pc-windows-msvc zip from the latest release.

Usage

celsius                          # current sky will open in the TUI
celsius -l Hamburg               # look up a place (can be done inside TUI as well)
celsius --lat 53.55 --lon 9.99   # coordinates
celsius --at 17                  # today at 17:00 UTC
celsius --at +3h                 # three hours from now
celsius --at 2026-06-21          # date alone, noon UTC
celsius --at 2026-06-21T17:00Z   # full ISO 8601
celsius --facing 0               # face north (default 180 = south)
celsius --bortle 7               # adjust visible stars + horizon glow for your sky
celsius --scene high_noon_clear  # a built-in sky, no network needed
celsius --scene ./my_sky.toml    # your own scene file

Seven scenes are compiled into the binary, so --scene works offline and on a fresh install: blue_hour_calm, golden_hour_cumulus, high_noon_clear, moonless_darksky, moonlit_clear_winter, overcast_night, stormy_afternoon_advancing. Pass a path instead of a name to render a scene TOML of your own.

Keys

Key	Action
← →	scrub one hour
tab / shift+tab	+24h / -24h
t	jump to now
space	pause / resume cloud drift
l	change location
r	retry weather fetch
?	keybinding help
q / esc	quit

Scene development

The unpublished Rust tool under tools/celsius-lab/ scaffolds scenes from production astronomy, renders previews, compares reference photographs in Oklab, and builds a labeled contact sheet without maintaining a second renderer.

just lab --help
just lab-render dawn
just lab-contact
just lab-diff dawn --against path/to/reference.jpg
just lab-new harbor_dawn 53.5511 9.9937 2026-04-11T06:14Z --out path/to/drafts/harbor_dawn.toml
just lab-new harbor_dawn 53.5511 9.9937 2026-04-11T06:14Z --visibility 18

See the celsius-lab guide for the scene and output layout.

Weather data by Open-Meteo.com (CC BY 4.0). Place names from GeoNames.