6 apps · open data · ECMWF · ERA5 · CAMS
Free weather & environment apps
Six free environmental tools built on open weather and climate data: snow forecasts and snowfall history, air pressure, climate history, UV index, pollen and air quality. No account or location permission required — just open and check.
Snowy Today covers snow from both ends: what is coming, and what is normal. The forecast answers “will it snow?” for cities worldwide with a plain verdict, the expected amount and a 7-day outlook, taken from the finest weather model that covers the place and then the global models, with every model's own figures in a table so you can see how much they agree.
The history is the larger half of each city page: 30 winters of snowfall statistics from ERA5, the ECMWF reconstruction of past weather. Does it snow here at all, and how much on average? When does the first snow usually fall and the last one melt? How many snow days a winter, how deep does it lie, when are the first and last frost, what are the odds of a white Christmas, and how do the last few winters compare with the long-term trend? Winter by winter, in tables and charts.
Features
- ✓Snow forecast: a direct answer and the amount, 7 days ahead, for cities worldwide
- ✓Every weather model's figures side by side, with the best local model first
- ✓Snowfall history: 30 winters of statistics per city, winter by winter
- ✓Average snowfall, first and last snow dates, snow days and snow depth
- ✓Frost dates, white-Christmas odds and the trend across recent winters
- ✓Does it snow in…? A straight answer for places where it rarely does
- ✓Available in 10 languages, with cm or inches on request
- ✓No account, no tracking cookies, installable as a PWA
Data sources
- Snow forecast: AROME, ICON-D2, ICON-EU, ECMWF IFS and the global models via Open-Meteo (open-source, commercial-use license)
- Snowfall history and statistics: ERA5 (ECMWF, open access), 30 winters, 1995/96–2024/25
- City names and coordinates: GeoNames (CC BY 4.0)
Barometer Today is a free reference for barometric pressure and, more usefully, for the direction it is heading. Every city page leads with the current sea-level pressure and then says in plain words how far it has moved over the past 24 hours: “up 8 hPa over the last 24 hours” answers far more real questions than the bare number does. Below that sit an hour-by-hour trace of the days behind and the week ahead, a sentence for each of the next seven days, and the daily rhythm where it is large enough to matter.
Figures come from the ECMWF IFS model at 0.25° resolution, served through a self-hosted Open-Meteo instance. Pressure is reduced to sea level everywhere, which is what national weather services publish and what makes two cities comparable; a high-altitude city also gets a clearly labelled second figure for what a barometer standing there would actually read. The site publishes no symptom forecast and no health scale: it says what the air is doing and leaves the conclusions to the reader.
Features
- ✓Current sea-level pressure for cities and towns worldwide
- ✓The 24-hour change, written as a sentence rather than an arrow
- ✓One graph, 7 days ahead, with the past shown as 48 hours, a week, or as far back as the data reaches
- ✓A plain-language card for each of the next seven days
- ✓Pressure at the city's own altitude, labelled, where elevation matters
- ✓hPa by default, with mmHg, inHg and kPa on request (1 hPa = 1 mbar)
- ✓Reference pages on method, units and altitude, each dated
- ✓No account, no cookies at all, installable as a PWA
Data sources
- Pressure forecast: ECMWF IFS via Open-Meteo (open-source, commercial-use license)
- City names and coordinates: GeoNames (CC BY 4.0)
- Elevation: Copernicus DEM via Open-Meteo
Weather Journey is a free historical weather service for 6,000+ major cities worldwide. Look up monthly average temperatures, all-time records, precipitation history, and climate anomalies going back to 1940 — then compare them to what's happening right now. Whether you're researching past weather events, planning a trip, or just curious how this January compares to every January on record, Weather Journey puts 85 years of data at your fingertips.
All historical climate data is built on ERA5, a scientific reanalysis of the global atmosphere produced by ECMWF. ERA5 covers the full period from 1940 to present on a consistent 31 km grid — making it the most reliable foundation for long-term weather trend analysis available without a subscription.
Features
- ✓Historical weather data from 1940 to present for 6,000+ major cities
- ✓Monthly average temperature, record highs, record lows, and anomalies
- ✓Monthly and annual precipitation history with long-term trend line
- ✓Today vs. average — is it warmer or colder than usual for this date?
- ✓Right now: live conditions with historical context side by side
- ✓Available in English, German, French, and Spanish
- ✓No account required, no personal data stored
Data sources
- Climate reanalysis: ERA5 (ECMWF, open access)
- Current conditions: Open-Meteo (open-source, commercial-use license)
- Geolocation: IP-based, server-side only
UVI Today is a free UV index forecast service. It shows the current UV level, hourly forecasts for today and tomorrow, a 5-day UV trend, sunrise/sunset times, and sun protection recommendations based on WHO guidelines. Your location is resolved via server-side IP geolocation — no browser prompt and no tracking.
UV index values are sourced from the Open-Meteo API, which derives its UV forecast from the Copernicus Atmosphere Monitoring Service (CAMS) operated by ECMWF. The five-level exposure scale (Low / Moderate / High / Very High / Extreme) follows the WHO classification.
Features
- ✓Real-time UV index for any location worldwide
- ✓Hourly UV forecast for today and tomorrow
- ✓5-day UV trend overview
- ✓Sunrise and sunset times
- ✓WHO-based exposure category (Low → Extreme)
- ✓Automatic location via IP geolocation — no browser prompts
- ✓No account required, no personal data stored
- ✓Mobile-friendly, installable as a PWA
Data sources
- UV index: Open-Meteo (open-source, commercial-use license)
- Atmospheric model: CAMS / ECMWF
- Geolocation: IP-based, server-side only
Pollen Today provides daily and multi-day pollen forecasts for six major allergenic plant types. The app covers European locations within the CAMS pollen model domain and resolves your location automatically — no browser prompts, no sign-up.
Pollen concentration data comes from the Open-Meteo API, which processes Copernicus CAMS pollen forecast output (SILAM model). The Low / Moderate / High / Very High scale follows EAACI threshold guidelines per pollen type.
Features
- ✓Daily pollen forecast for 6 plant types: alder, birch, grass, mugwort, olive, ragweed
- ✓Multi-day forecast (several days ahead)
- ✓Low / Moderate / High / Very High scale per EAACI thresholds
- ✓Automatic location via IP geolocation — no browser prompts
- ✓Coverage: European locations (CAMS pollen model area)
- ✓No account required, no personal data stored
Data sources
- Pollen forecast: Open-Meteo (open-source, commercial-use license)
- Atmospheric model: CAMS / ECMWF (SILAM dispersion model)
- Geolocation: IP-based, server-side only
Air Index Today is a free air quality index (AQI) service. It shows the current AQI for any city, hourly forecasts for today and tomorrow, a 5-day AQI trend, individual pollutant levels, and health advice based on the EPA AQI scale. Your location is resolved via server-side IP geolocation — no browser prompt and no tracking.
Air quality data is sourced from the Open-Meteo Air Quality API, which derives its forecasts from the Copernicus Atmosphere Monitoring Service (CAMS) operated by ECMWF. The six-level AQI scale follows the U.S. EPA classification.
Features
- ✓Real-time AQI for any city worldwide
- ✓Hourly AQI forecast for today and tomorrow
- ✓5-day AQI trend overview
- ✓Pollutant breakdown: PM2.5, PM10, NO₂, O₃, SO₂, CO
- ✓EPA AQI scale: Good → Hazardous
- ✓Health advice per AQI level
- ✓Automatic location via IP geolocation — no browser prompts
- ✓No account required, no personal data stored
- ✓Mobile-friendly, installable as a PWA
Data sources
- AQI & pollutants: Open-Meteo (open-source, commercial-use license)
- Atmospheric model: CAMS / ECMWF
- Geolocation: IP-based, server-side only
More apps coming
We're working on additional open-data environmental tools. If you have a suggestion or want to get in touch, drop us a line.
