fmi-weather-client 1.0.0
Library for fetching weather information from Finnish Meteorological Institute (FMI)
Requires Python: >=3.10

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# Finnish Meteorological Institute Weather
Library for fetching weather information from
[Finnish Meteorological Institute (FMI)](https://en.ilmatieteenlaitos.fi/open-data). 

If you want to know how FMI API works, you can check out their [WFS Examples and Guidelines](https://en.ilmatieteenlaitos.fi/open-data-manual-wfs-examples-and-guidelines) page.

For the current weather information, this library requests observations from the past `10` minutes using timestep `10`. Based on my tests this gave pretty reliable results from different weather stations.

Originally, I created this for myself to get FMI weather data to [Home Assistant](https://www.home-assistant.io/). I am not a meteorologist so if you are more weather-savvy, feel free to contribute and provide improvements! 💖

**FYI: I don't use Home Assistant or this library anymore, so I may not know if things are broken or need updating. However, I'm more than happy to maintain this library, so if you find a bug or a need to update a dependency, feel free to file an issue. Even better, file a pull request that fixes the issues! 😉 💖**

## How to use

Working example can be found in [example.py](example.py).

### Install

```
$ pip install fmi-weather-client 
```

### Get weather, forecasts, and observations
You can get the weather using the following functions:
- `weather_by_place_name(place_name)`
- `weather_by_coordinates(latitude, longitude)`
- `observation_by_station_id(fmi_station_id)`
- `observation_by_place(place_name)`

Example:
```python
import fmi_weather_client as fmi
from fmi_weather_client.errors import ClientError, ServerError

try:
    weather = fmi.weather_by_place_name("Jäppilä, Pieksämäki")
    if weather is not None:
        print(f"Temperature in {weather.place} is {weather.data.temperature}")
except ClientError as err:
    print(f"Client error with status {err.status_code}: {err.message}")
except ServerError as err:
    print(f"Server error with status {err.status_code}: {err.body}")
```

You can get the forecasts using the following functions:
- `forecast_by_place_name(place_name, [timestep_hours=24], [forecast_points = 4])`
- `forecast_by_coordinates(latitude, longitude, [timestep_hours=24], [forecast_points = 4])`

Example:
```python
import fmi_weather_client as fmi
from fmi_weather_client.errors import ClientError, ServerError

try:
    forecast = fmi.forecast_by_coordinates(60.170998, 24.941325)
    for weather_data in forecast.forecasts:
        print(f"Temperature at {weather_data.time}: {weather_data.temperature}")
except ClientError as err:
    print(f"Client error with status {err.status_code}: {err.message}")
except ServerError as err:
    print(f"Server error with status {err.status_code}: {err.body}")

```

You can get the observation data from a station using the following functions:
- `observation_by_station_id(fmi_sid)`

To get a weather observation from a station, you must provide a station ID. IDs can be found on [FMI's station list](https://www.ilmatieteenlaitos.fi/havaintoasemat). Note that weather observations are available only from **weather stations**. These are the ones with `sää` in the `Ryhmä` column.

Example:
```python
import fmi_weather_client as fmi
from fmi_weather_client.errors import ClientError, ServerError

try:
    weather = fmi.observation_by_station_id(101794)
    if weather is not None:
         print(f"Temperature at {weather.place} is {weather.data.temperature}")
except ClientError as err:
    print(f"Client error with status {err.status_code}: {err.message}")
except ServerError as err:
    print(f"Server error with status {err.status_code}: {err.body}")

```

All functions have asynchronous versions available with `async_` prefix.

### Errors

##### ClientError
Happens if FMI service returns `400-499`. This can happens for example if:
- Provided coordinates are invalid
- Provided place is not recognized
- Weather data is not available

Error object contains status code and human-readable error message from FMI service.

##### ServerError
Happens if FMI service returns any other error.

Error object contains status code and raw response body from FMI service


### Weather data
FMI provides the following commonly used information:
- Temperature (°C)
- Pressure (hPa)
- Humidity (%)
- Wind direction (°)
- Wind speed (m/s)
- Wind gust (m/s)
- Dew point (°)
- Cloud coverage (%)
- Precipitation intensity (mm/h)
- Symbol [Documentation in Finnish](https://www.ilmatieteenlaitos.fi/latauspalvelun-pikaohje)
- Feels like temperature (°C), calculated from weather data [Documentation in Finnish](https://tietopyynto.fi/files/foi/2940/feels_like-1.pdf)


There are also other information available. Check [models.py](fmi_weather_client/models.py) and FMI documentation for
more info.

## Development

### Setup
Create and activate a virtual environment
```
$ python -m venv venv
$ source venv/bin/activate
```

Install required packages
```
$ make setup
```

Deactivate virtual environment when you are done
```
$ deactivate
```

### Run tests
This will run unit tests and code quality checks
```
$ make test
```