Openweathermap Rain sensor not reporting correctly

[txNgineer]

Home Assistant release with the issue:

0.85.1 and prior

Last working Home Assistant release (if known): none, to my knowledge

Operating environment (Hass.io/Docker/Windows/etc.):

homeassistant on Raspian running on Raspberry Pi 3. OS: Raspbian 9.6 stretch Kernel: armv7l Linux 4.14.79-v7+ CPU: ARMv7 rev 4 (v7l) @ 1.2GHz RAM: 346MiB / 926MiB

Component/platform:

sensor.owm_rain Likely code error in: homeassistant/components/openweathermap.py

Description of problem: The sensor always shows "Not Raining" even when a query to the API directly shows a value for the rain sensor.

Problem-relevant configuration.yaml entries and (fill out even if it seems unimportant):

in sensors.yaml
#### Openweathermap ##############################
  - platform: openweathermap
    api_key: !secret openwx_API
    forecast: True
    monitored_conditions:
      - weather
      - temperature
      - wind_speed
      - wind_bearing
      - humidity
      - pressure
      - clouds
      - rain
      - snow

Traceback (if applicable):

2019-01-26 20:54:34 ERROR (MainThread) [homeassistant.helpers.entity] Update for sensor.owm_rain fails
Traceback (most recent call last):
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/helpers/entity.py", line 204, in async_update_ha_state
    yield from self.async_device_update()
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/helpers/entity.py", line 327, in async_device_update
    yield from self.hass.async_add_job(self.update)
  File "/usr/lib/python3.5/asyncio/futures.py", line 380, in __iter__
    yield self  # This tells Task to wait for completion.
  File "/usr/lib/python3.5/asyncio/tasks.py", line 304, in _wakeup
    future.result()
  File "/usr/lib/python3.5/asyncio/futures.py", line 293, in result
    raise self._exception
  File "/usr/lib/python3.5/concurrent/futures/thread.py", line 55, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/srv/homeassistant/lib/python3.5/site-packages/homeassistant/components/sensor/openweathermap.py", line 164, in update
    self._state = round(data.get_rain()['3h'], 0)
KeyError: '3h'

Additional information: Line 164 of the python file gets the rain data with

       if data.get_rain():
           self._state = round(data.get_rain()['3h'], 0)
           self._unit_of_measurement = 'mm'

But this is not suitable in all situations. For example the API query and JSON response at this time show: Query: https://api.openweathermap.org/data/2.5/weather?zip=77423,us&units=imperial&id= with Response: {"coord":{"lon":-96,"lat":29.83},"weather":[{"id":500,"main":"Rain","description":"light rain","icon":"10n"}],"base":"stations","main":{"temp":55.29,"pressure":1021,"humidity":84,"temp_min":53.06,"temp_max":57.2},"visibility":16093,"wind":{"speed":7.47,"deg":159.004},"rain":{"1h":0.25},"clouds":{"all":90},"dt":1548554100,"sys":{"type":1,"id":3968,"message":0.0038,"country":"US","sunrise":1548594998,"sunset":1548633431},"id":420037180,"name":"Houston","cod":200} Notice that only a 1h number is shown and no 3h is available for this location. Refer to API note that Rain item is showing "1h" in the case when data are received from weather stations directly. . Also note that this data is often a fraction of a mm and should be rounded to 2 decimal places.

[txNgineer]

Here is my understanding of the API conditions:

• Parameter "rain" is missing when the condition is "not raining"
• Direct reporting stations will have a value field of "1h" for rain value when raining
• Non-reporting stations will have a value field of "3h" and model results in the value
• It is possible, but unconfirmed, that Direct reporting stations will also report a value field of "3h" when the rain has persisted for multiple hours. The condition logic in line 164 of the script does not account for all of the above possibilities. I will be very glad to help with the programming, testing, and issuing a pull request if a developer will advise whether there are other referencing scripts that might be affected by any change to the openweathermap.py sensor component script. I do not want to be changing things without understanding the broader picture.

[B-Kramer]

If some digs into this, I think the api condition codes need to be changed too... "exceptional" comes up too often, when better information is being reported by the api.

[txNgineer]

The biggest issue I have had when digging into it is the lack of information from the API web site on what the allowable values are. I will try contacting OpenWeatherMap directly and see if I can get any info directly. Should a more complete API document become available, I will be glad to do the digging. While I can code the changes, my style may not be properly "pythonic", and while it works for me it makes me hesitant to share.

[txNgineer]

Further info from the API shows the JSON decoder must handle missing parameters more fully:

If you do not see some of the parameters in your API response it means that these weather phenomena are just not happened for the time of measurement for the city or location chosen. Only really measured or calculated data is displayed in API response.

[txNgineer]

I did find the following table on the weather station POST description. It has a minimum of what needs to be considered to avoid exceptions (Note - the units could also be returned in imperial quantities if the GET request specified them that way):

Parameter	Type & Units	Description
station_id		The internal ID of the station which is generated during creation
dt	Unix Timestamp	Time of measurement
temperature	Celsius	The air temperature
wind_speed	m/s	Wind speed
wind_gust	m/s	Maximum speed of wind gusts
wind_deg	Degrees from 0 to 360	Wind direction
pressure	Hectopascal	Atmospheric pressure
humidity	%	Relative air humidity
rain_1h	mm	Rainfall in the last hour
rain_6h	mm	Rainfall in the last 6 hours
rain_24h	mm	Rainfall for the last days
snow_1h	mm	Snow in the last hour
snow_6h	mm	Snow in the last 6 hours
snow_24h	mm	Snow for the last days
dew_point	Celsius	Dew point
humidex	Celsius	Index of temperature and humidity
heat_index	Celsius	Heat index
visibility_distance	km	Distance of direct visibility, METAR
visibility_prefix	N, E, S, W	Prefix at distinctions of visibility in the directions, METAR
clouds[]:distance	m	Height of the lower bound of overcast, METAR
clouds[]:condition	SKC, NSC, FEW, SCT, BKN, OVC	Cloud amount, METAR
clouds[]:cumulus	CB, TCU	Convective overcast, METAR
weather[]:precipitation		Additional description, METAR
weather[]:descriptor		Additional description, METAR
weather[]:intensity		Additional description, METAR
weather[]:proximity		Additional description, METAR
weather[]:obsruration		Additional description, METAR
weather[]:other		Additional description, METAR

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