Overview

Introduction

Atmos is a sleek, minimal weather app that delivers real-time forecasts using the free and privacy-respecting Open-Meteo API. No account needed — just open it and know the weather.

Real-time Weather
Current temperature, feels like, humidity, wind and more.
7-Day Forecast
Full weekly overview with daily highs and lows.
Hourly Breakdown
Scrollable hourly timeline for the next 24 hours.
City Search
Search any city worldwide using geocoding.
Privacy First
No tracking, no accounts, no data stored.
Zero Build Step
Pure HTML, CSS & JavaScript. No bundler required.
Atmos is hosted at useatmos.me and its documentation lives at docs.useatmos.me. The project is fully open-source on GitHub.
Setup

Installation

Atmos requires no build step. Running it locally is as simple as cloning the repository and opening index.html in a browser.

Prerequisites

  • A modern web browser (Chrome, Firefox, Safari, Edge).
  • Git (optional — you can also download the ZIP).
  • A local HTTP server is recommended for accurate geolocation (see note below).

Clone & Run

git clone https://github.com/kebabmario/atmos.git
cd atmos

# Option A: open directly
open index.html

# Option B: serve with any static server (recommended)
npx serve .
# or
python3 -m http.server 8080

Then open http://localhost:8080 in your browser.

GitHub Pages deployment

The repository is already configured to deploy automatically via GitHub Pages. The main site (useatmos.me) is served from the root, while the docs site (docs.useatmos.me) is served from the /docs folder.

Custom domain setup: The root CNAME file contains useatmos.me. The docs/CNAME file contains docs.useatmos.me. GitHub Pages will serve each folder from its respective domain when both are configured in the repository settings.

Setting up docs.useatmos.me

  1. In your DNS provider, add a CNAME record pointing docs.useatmos.me → kebabmario.github.io.
  2. In the GitHub repository settings under Pages, set the source to the docs/ folder on the main branch.
  3. In the Custom domain field enter docs.useatmos.me and save. GitHub will create (or verify) docs/CNAME automatically.
  4. Enable Enforce HTTPS once the certificate is issued.
Do not modify the root CNAME file — it controls the main useatmos.me domain. The docs-specific docs/CNAME is separate and independent.
Guide

Usage

Learn how to use Atmos to get weather data for any city, and how the Open-Meteo API is integrated under the hood.

Getting weather for a city

  1. Type a city name

    Enter any city name in the search bar at the top of the app, e.g. London.

  2. Press Go or hit Enter

    The app will geocode the city name using the Open-Meteo geocoding API and retrieve coordinates.

  3. View the forecast

    Current conditions, hourly forecast for the next 24 h, and a 7-day daily outlook are displayed immediately.

Open-Meteo API Integration

Atmos uses two Open-Meteo endpoints: the Geocoding API to convert city names to coordinates, and the Forecast API to retrieve weather data. Both are free, require no API key, and do not track users.

Endpoint Purpose Key Parameters
geocoding-api.open-meteo.com/v1/search City name → lat/lng name, count, language
api.open-meteo.com/v1/forecast Weather data latitude, longitude, hourly, daily, current_weather

Forecast variables fetched

  • Current: temperature, windspeed, weathercode
  • Hourly: temperature_2m, precipitation_probability, weathercode, apparent_temperature
  • Daily: temperature_2m_max, temperature_2m_min, weathercode, sunrise, sunset, precipitation_sum

Example request

const GEO_URL = 'https://geocoding-api.open-meteo.com/v1/search';
const WX_URL  = 'https://api.open-meteo.com/v1/forecast';

async function fetchWeather(city) {
  // 1. Geocode
  const geo = await fetch(`${GEO_URL}?name=${encodeURIComponent(city)}&count=1`);
  const { results } = await geo.json();
  const { latitude, longitude, name } = results[0];

  // 2. Fetch forecast
  const wx = await fetch(
    `${WX_URL}?latitude=${latitude}&longitude=${longitude}` +
    `¤t_weather=true` +
    `&hourly=temperature_2m,precipitation_probability,weathercode` +
    `&daily=temperature_2m_max,temperature_2m_min,weathercode,sunrise,sunset` +
    `&timezone=auto`
  );
  return wx.json();
}

Full API documentation is available at open-meteo.com/en/docs.

Data Quality

Accuracy

Atmos sources its data from Open-Meteo, which aggregates multiple high-resolution global numerical weather prediction (NWP) models.

Weather models used

Open-Meteo automatically selects the best available model for your location:

  • ECMWF IFS — European Centre for Medium-Range Weather Forecasts (global, high resolution).
  • GFS — NOAA Global Forecast System (Americas & global).
  • DWD ICON — German Weather Service (Europe, very high resolution).
  • MeteoFrance AROME — France & surrounding regions.
  • BOM ACCESS — Australia & Oceania.

Limitations

  • Forecast accuracy degrades beyond 7 days.
  • Local microclimates (valleys, urban heat islands) may not be fully captured.
  • Precipitation predictions are probabilistic — exact timing can vary by 1–2 hours.

Update frequency

Open-Meteo updates its forecasts every hour for short-range models, and every 6–12 hours for medium-range models. Atmos fetches fresh data on each search.

Open-Meteo reports a median absolute error of ≤ 1.5 °C for 24-hour temperature forecasts globally. See their benchmarks for details.
Data & Privacy

Privacy

Atmos is built with privacy at its core. We do not collect, store, or share any personal data.

What Atmos does not do

  • No user accounts or sign-up required.
  • No cookies set by the Atmos application.
  • /li>No analytics or telemetry.
  • Your location is never sent to our servers.
  • No data is stored between sessions.

Third-party services

Atmos makes requests directly from your browser to the following third-party APIs:

  • Open-Meteo (terms) — receives your city's coordinates to return weather data. Open-Meteo is GDPR-compliant and does not store personal data.
  • Google Fonts — loads the Inter typeface. Your browser will connect to Google's CDN; see Google Fonts privacy.

Self-hosting

If you require full data sovereignty, Atmos can be self-hosted by cloning the repository and replacing the Google Fonts link with a locally bundled font. No server-side component is needed.

Acknowledgements

Credits

Atmos stands on the shoulders of open-source giants. Here's a thanks to everyone who made it possible.

Data

  • Open-Meteo — Free, open-source weather API. Absolutely no API key required. Free & Open

Fonts

  • Inter by Rasmus Andersson — the typeface used throughout the app and docs. SIL OFL

Icons & Design

  • Weather condition icons are rendered as Unicode emoji for maximum compatibility.
  • Color palette inspired by clear night-sky blues.

Built with

  • Vanilla HTML, CSS & JavaScript — zero runtime dependencies.
  • Hosted on GitHub Pages — free, reliable, and fast.

Contributing

Contributions are welcome! Open an issue or pull request on GitHub. Please keep PRs focused and follow the existing code style.

If Atmos has been useful to you, consider giving the repository a ⭐ on GitHub!