I don’t think there is any capability related to weather assessment or prediction…Maybe I’m wrong, if so, I will delete it.
This capability should include the folllowing attributes:
weatherText
forecastHigh
forecastLow
wind
windDirection
feelsLike
percentPrecip
alert
uvIndex
water (wet, dry, and snow…)
precipitation (rain precipitation in mm or inch)
Do you have an example of a physical device with its actual parameters?
Also, just in case you’re just thinking this is information it would be nice for ST customers to have (as opposed to a device that a coder would want to use), there is already a standard smartapp that does this, SmartWeather Station Controller. It pulls from a web service.
Yes, there are already device types that do that, such as the smart weather station tile, but I think that we need a capability that transcends physical and virtual devices.
As for the physical devices on the market, two examples that come to my mind are the netatmo and its various modules and the Davis weather station.
Bye.
I believe Netatmo has been in the ST labs for a few months. What’s missing from that device type?
https://support.smartthings.com/hc/en-us/articles/202989470-Connecting-Netatmo-To-SmartThings
I only found the “Smart Weatherstation” Device Type, and it looks like it has a whole bunch of ad hoc Attributes.
This is a case where we have no “compound” Capability called “Weather Station” (or Forecast or Prediction…); but instead 3 granular Capabilities are used instead.
And so… multiple new Capabilities are required to cover the list of Attributes (some Attributes belong together, others do not).
capability "Illuminance Measurement"
capability "Temperature Measurement"
capability "Relative Humidity Measurement"
attribute "localSunrise", "string"
attribute "localSunset", "string"
attribute "city", "string"
attribute "timeZoneOffset", "string"
attribute "weather", "string"
attribute "wind", "string"
attribute "weatherIcon", "string"
attribute "forecastIcon", "string"
attribute "feelsLike", "string"
attribute "percentPrecip", "string"
attribute "alert", "string"
attribute "alertKeys", "string"
attribute "sunriseDate", "string"
attribute "sunsetDate", "string"
I like that idea. How about capability.fortuneTelling ?
Sorry, could not resist. 
I will rename this capability to simply weather forecasting… However, we all know that weather forecasts are often more like fortune telling rather than anything really deterministic…
I see it’s been a while since this topic was opened, but in light of the recent Rule Machine and Trigger Happy apps, I’d like to push for a weather capability to be created. This would be quite useful in creating weather-based rules using these apps.