Værmeldingen (“the weather forecast” in Norwegian) is a complete weather app for Norway. One device gives you the forecast from several weather models, radar nowcast, new snow and snow depth, the risk of slippery roads, air quality, MET weather warnings, MET’s own text forecast and, if you like, the readings from your own weather station. The forecast works anywhere, but the app is made first and foremost for Norway.
Install the test version of Værmeldingen
Why I made it
I used the Værvarsel (Yr) app, but some of its flow card problems have been reported in its forum topic for a long time without being fixed:
- Tags such as Rain next 30 minutes disappear from the device when the radar nowcast is more than 15 minutes old, so flows that use them fail with “unknown tag”.
- Time spans across midnight, such as 22:00–06:00, always fail.
- A time span that has already passed gives an error instead of answering no.
So I built a new app where these work, and added what I was missing:
- More weather models. Værvarsel uses one forecast, MET’s. A single model is sometimes spot on and sometimes far off. Værmeldingen combines five (MET Nordic, ECMWF, DWD ICON, UK Met Office and NOAA GFS), gives the most weight to the one that does best at each lead time and leaves out the biggest outlier. For the next two hours it uses MET’s radar nowcast, updated every five minutes.
- Snow. I could not find a Homey app that tells how much new snow is coming or how deep the snow is. Værmeldingen does both, using seNorge’s snow model from NVE and MET (see Snow below).
- Weather warnings. MET’s weather warnings are built in, so you don’t need a separate app for them.
- Your own weather station. Use the readings from your own station, such as Netatmo, for the current weather, and let it adjust the temperature for the next few hours (see Your own weather station below).
- Slippery roads and air quality. The risk of slippery roads, worked out from precipitation and temperature, and MET’s air quality forecast for where you live.
Værmeldingen supports all the flow cards from Værvarsel and MET Varsel, so you can switch without losing anything.
Sources
| Source | Used for |
|---|---|
| MET Nordic (MET Norway, the same data as Yr) | Main forecast, most weight the first two days |
| ECMWF, DWD ICON, UK Met Office, NOAA GFS (via Open-Meteo) | Weighted average; ECMWF takes over further ahead |
| MET Nowcast | Radar precipitation, the next two hours (Nordic countries) |
| MetAlerts | Weather warnings |
| seNorge (NVE and MET) | Snow depth in Norway, every square kilometre |
| MET Sunrise | Sun and moon |
| MET Textforecast | The meteorologists’ own text forecast for your region |
| MET Air Quality Forecast | Air quality in Norway, hour by hour |
What you get
- Now: weather type, temperature, feels like, wind, gusts, wind direction, humidity, pressure, cloud cover, fog, chance of thunder and UV.
- Precipitation: now, the next 30 minutes, the next hour and the next 6 hours, the chance of precipitation and when it starts.
- Snow: new snow for the next 6 and 24 hours, and snow depth (see below).
- Temperature: lowest and highest in the next 6 hours.
- Weather warnings from MET for your location, with level, type and duration.
- Sun and moon: sunrise, sunset, sun hours today and tomorrow, and moon phase.
- Slippery roads: the risk now and the highest risk in the next 6 hours (see below).
- Air quality (Norway): MET’s air quality index and level (low, moderate, high, very high), PM2.5, PM10 and NO₂, now and hour by hour.
- Model agreement: how alike the models are, so you can see how certain the forecast is. For the next 24 hours, the coming hours or a time span.
- Text forecast for today, tomorrow and the day after, ready to be spoken or sent as a notification, and MET’s own text forecast for your region (Norway, in Norwegian).
- Dashboard widget with now, the next hours and three days.
Snow
- New snow is the averaged precipitation times the share the models expect to fall as snow (from the models’ snowfall and MET’s weather symbol, otherwise the temperature).
- Cold snow gives more centimetres: 1 mm of precipitation gives about 0.8 cm of wet snow at 0 °C, 1 cm at −2 °C, 1.5 cm at −10 °C and 1.8 cm at −15 °C and colder.
- Snow depth in Norway comes from seNorge, which models snowfall, melting and settling every three hours a few days ahead. If your location is in the sea on their map, the nearest land cell is used. Further ahead, and outside Norway, the change in the models’ snow depth is followed, so the depth also drops when it gets mild.
- New snow is only the snow that falls; melting is not subtracted. Use the snow depth cards for the net result.
Slippery roads
A risk from 0 to 100, hour by hour. It is highest when rain falls at around 0 °C or lower (100), or on frozen ground after a cold spell (80), and when it freezes after recent precipitation (70). Wet snow and sleet give 60, colder snowfall 40 and frost on a damp night 30. The hours just before now count too, so rain that freezes overnight is caught. It is an estimate from the forecast, not a road report.
Your own weather station
Do you have a weather station in Homey, such as Netatmo? Then its readings can be used for the current weather. You send them to Værmeldingen with a flow.
- Which readings: temperature, humidity, pressure, wind, gusts and wind direction. Feels like and the 6-hour min/max are adjusted to match. Readings older than three hours are not used.
- The next few hours: if your station is warmer or colder than the models, that difference is added to the temperature forecast. It counts fully now and fades out over six hours, so now and the next hours fit together.
- The forecast further ahead still comes from the weather models.
- See what is used: the device setting Own weather station under Status tells which readings come from your station, when the last one arrived and how much the temperature is adjusted.
How to set it up (Netatmo as an example):
- Create a new flow.
- When: your Netatmo outdoor module → The temperature changed.
- Then: Værmeldingen → Use reading from own weather station. Choose temperature (°C) as the measurement, and the Temperature tag from the Netatmo module as the value.
- Do the same for humidity, pressure and wind if you like: one flow per measurement, or several Then cards in a flow that runs every 10 minutes. Wind can be sent in m/s or km/h; pick the matching measurement in the card.
- To go back to the weather models only, use the card Stop using own weather station.
Flow cards
More than 100 flow cards. A few examples:
- Precipitation starts within 15 minutes
- The highest temperature tomorrow between 08:00 and 16:00 is below 0 °C
- Total new snow tomorrow is above 10 cm
- The snow depth is below 5 cm
- A weather warning at orange level or higher is active
- The highest risk of slippery roads in the next 6 hours is above 60 %
- The air quality level is at least moderate
- The weather changed
- Get MET’s text forecast for tomorrow
Most values have three condition cards: now, the coming hours (highest, lowest, average or total) and a time span on a day (today, tomorrow or the day after). Time spans across midnight work, and a time span that has already passed answers no.
Getting started
- Install the app and add a device → Værmeldingen.
- It uses Homey’s location. To follow another place, such as your cabin, enter latitude and longitude in the device settings and add more devices.
- Optional: send readings from your own weather station with a flow (see above).
Device settings
- Location: latitude and longitude. Leave empty to use Homey’s location.
- Counts as rain from (mm/h): the limit for It started raining, It is raining now and when precipitation starts. Default 0.1.
- Status: location in use, coverage, own weather station, sources in use, last updated and last errors.
Support
Please post in this thread. It helps a lot if you include:
- A screenshot of the device settings under Status.
- Roughly where you are (town is enough) and what you expected to see.
- For flow cards: a screenshot of the flow.
Suggestions are very welcome. I am quick to add new flow cards and values.
Requirements
All Homeys that run apps locally with Homey 12.4 or newer: Homey Pro, Homey Pro mini and Homey Self-Hosted Server. Homey Cloud is not supported.
Made for Norway. Outside Norway the forecast works, but weather warnings, snow depth from seNorge, air quality and MET’s text forecast are only available for Norway, and the radar nowcast only for the Nordic countries. The app tells you when you add the device, and Coverage under Status shows what is missing.
Data from MET Norway (CC BY 4.0), Open-Meteo.com (CC BY 4.0) and seNorge.no by NVE and MET (CC BY 4.0).
Changelog in the next post.
