OpenWeatherMap how to implement units into table

Currently trying to build a very basic weatherdata display, receiving data from openweathermap.org.

Using a curl session to get the data, afterwards I am decoding with json_decode and want to display the data inside a basic table.

I would like to implement the equivalent units in a third column (degrees, degrees celsius, hPa, %, km/h, ...) with if statements (if temp -> °C). Unfortunatly I dont know how to do this, thank you for your help.

current table

My code:

$weatherData = json_decode($response, true);

echo "<table><tr><th>Category</th><th>Data</th><th>Units</th></tr>";
foreach($weatherData as $key => $value) {
    foreach($value as $weatherKey => $weatherValue) {
        echo "<tr><td>{$weatherKey}</td><td>{$weatherValue}</td><td>X</td></tr>";
    }
}
echo "</table>";