Translatable Weathercode Description Field

As suggested in #262 and #228 it would be nice to have a weathercode description that could be translated into different languages and using a lang parameter people get the description in ther language. It could be added when someone chooses to include the weathercode. Here's a suggestion for what could be used for English:

Code	Description
0	Clear
1	Mostly Clear
2	Partly Cloudy
3	Cloudy
45	Fog
48	Freezing Fog
51	Light Drizzle
53	Drizzle
55	Heavy Drizzle
56	Light Freezing Drizzle
57	Freezing Drizzle
61	Light Rain
63	Rain
65	Heavy Rain
66	Light Freezing Rain
67	Freezing Rain
71	Light Snow
73	Snow
75	Heavy Snow
77	Snow Grains
80	Light Rain Shower
81	Rain Shower
82	Heavy Rain Shower
85	Snow Shower
86	Heavy Snow Shower
95	Thunderstorm
96	Hailstorm
99	Heavy Hailstorm

Is weathercode 96 and 99 thunderstorms with hail or just stronger thunderstorms? The docs say it's supposed to be hail but I don't think the code calculation reflects that or maybe it does and I don't know how to read the code properly.

This is more of an enhancement no? There is the table with the weathercode description on the API docs page but there is no field on the API which returns the description in that table.

It would be nice to have a field on the API which returns a description of the weathercode for people to use in their apps and if you make it translatable people can get the description in their native language.

[long-nguyen]

Hi, I want to ask why your WMO code is lacking from global list?
https://www.nodc.noaa.gov/archive/arc0021/0002199/1.1/data/0-data/HTML/WMO-CODE/WMO4677.HTM

I looked at the codes using the link you provided and I see that there are a lot of similar codes so I think that the ones chosen were for simplicity. Plus trying to calculate some of the codes might be too complicated and not worth adding

The current list is pretty good but the only codes I would consider adding would be these 4 though I'm not sure how easy they would be to calculate.

5 (Haze)
10 (Mist)
79 (Ice Pellets/Sleet)
97 (Heavy Thunderstorm [Thunderstorm, heavy, without hail but with rain and/or snow at time of observation])

Both codes 96 and 99 are thunderstorms with hail leaving no heavy thunderstorms without hail which is code 97.

I did update some of my descriptions to match the ones from that link and I think that depositing rime fog and freezing fog are the same? Not a weather expert but that's what I found using Google.

[patrick-zippenfenig]

The current selection of weather codes is based on the published weather codes from the German weather service. For most weather models, they are calculated from forecast parameters like clouds, precipitation, snow, cape, lifted index and visibility.

As @Acraeus mentioned, some weather codes are challenging to estimate from modelled weather forecasts.

5 (Haze), 10 (Mist) and fog forecasts are very inaccurate as they are very local and only occur with specific conditions. Right now, only fog is given as a weather code.

79 (Ice Pellets/Sleet) are indicated in some weather models, but they are very similar to freezing rain (66,67) or snow grains (77)

97 (Heavy Thunderstorm) I might add this one in the future

5 (Haze), 10 (Mist) and fog forecasts are very inaccurate as they are very local and only occur with specific conditions. Right now, only fog is given as a weather code.

I'm not an expert at this kind of stuff calculated from visibility and humidity. Haze occurs in drier conditions whereas mist and fog occur in more humid conditions.

79 (Ice Pellets/Sleet) are indicated in some weather models, but they are very similar to freezing rain (66,67) or snow grains (77)

The main difference between Freezing Rain and Sleet is when the precipitation freezes. From what I see there is a slight difference between snow grains and sleet. I found these definitions from the WMO: https://cloudatlas.wmo.int/en/snow-grains.html and https://cloudatlas.wmo.int/en/ice-pellets.html

[phillipseamore]

Haze would usually be derived from aerosol/air quality forecasts, usually PM2.5 concentration thresholds (PM2.5 > 50 / 100 / 200 µg/m³). These thresholds might be very different depending on climate or country.

Mist could be something like:
(dewpoint 2m - ground temp) > -0.3 && windspeed_10m < 5

It's also important to know that the WMO codes are designed for manned observation and so do not necessarily mean that they can be used with DMO output - though they often are.

If we're going to use aerosol/air quality to calculate Haze then we could also add in the Smoke (4) weathercode since I think it's calculated using PM2.5 like Haze is. You could also maybe add in Sand/Dust (9) since I think it's calculated using PM10. I'm not a weather expert so I could be wrong here in case feel free to correct me.

In order to do those calculations you'd need to use the data from the Air Quality models which might be tricky to include in the current weather API. If it's too tricky to calculate then only adding in code 97 would be fine.

[patrick-zippenfenig]

Yes, dust and other aerosols like smoke are available in global air pollution models. Some are available in the Air Quality API others are available from the CAMS global atmospheric composition forecasts.

Adding dust/smoke/haze is a good idea, but can lead to inconsistencies as many different models are combined. It also raises issues like breaking changes to the API as new codes my break existing implementations from other users. Once option could be a weathercodeV2 with an extended set that is also more optimised for DMO instead of manned observations.

If using the AQI is going to lead to inconsistencies then maybe it can go into the backburner to be added later. I understand that changing the weathercode field would break users implementations but I still think adding code 97 would make sense. You could always add it as an additional query parameter and add it to the main variable down the line so people have a chance to add it before breaking things?

I feel like this issue is starting to get a bit off-topic with all the discussion around adding in new weathercodes. That discussion should probably be it's own separate issue.

[mirix]

I have created a JSON file mapping WMO code 4677 to:

1. A short description in English.

2. Animated SVG icons (https://basmilius.github.io/weather-icons/index-line.html)

The Open-Meteo-powered app is up and running here (beta):

https://huggingface.co/spaces/mirix/weather_for_hikers

You can check the code and the mapping.

[Benjamin-Loison]

Based on https://open-meteo.com/en/docs#weather_variable_documentation:

JSON:

{
    "0": "Clear sky",
    "1": "Mainly clear",
    "2": "Partly cloudy",
    "3": "Overcast",
    "45": "Fog",
    "48": "Depositing rime fog",
    "51": "Light drizzle",
    "53": "Moderate drizzle",
    "55": "Dense drizzle",
    "56": "Light freezing drizzle",
    "57": "Dense freezing drizzle",
    "61": "Slight rain",
    "63": "Moderate rain",
    "65": "Heavy rain",
    "66": "Light freezing rain",
    "67": "Heavy freezing rain",
    "71": "Slight snow fall",
    "73": "Moderate snow fall",
    "75": "Heavy snow fall",
    "77": "Snow grains",
    "80": "Slight rain shower",
    "81": "Moderate rain shower",
    "82": "Violent rain shower",
    "85": "Slight snow shower",
    "86": "Heavy snow shower",
    "95": "Thunderstorm",
    "96": "Slight hail thunderstorm",
    "99": "Heavy hail thunderstorm"
}

Personal notes: Benjamin_Loison/Voice_assistant/issues/33#issuecomment-11386192