Hello Gand,
you can test following code (replace the existing code at line 113:
<?php //windrun
if ($weather["wind_units"]=='kts'){echo"<div class=tempmodulehome0-5c>". " ".(number_format($weather["windrun34"]*1.852,1)).''.'<smalltempunit2> ';};
if ($weather["wind_units"]=='km/h'){echo"<div class=tempmodulehome0-5c>". " ".(number_format($weather["windrun34"],1)).''.'<smalltempunit2> ';};
if ($weather["wind_units"]=='mph'){echo"<div class=tempmodulehome0-5c>". " ".(number_format($weather["windrun34"],1)).''.'<smalltempunit2> ';};
if ($weather["wind_units"]=='km/h'){echo 'km';};
if ($weather["wind_units"]=='mph'){echo 'mi';};
if ($weather["wind_units"]=='kts'){echo 'km';};?></div></div></div>
it runs for me, have select kt's (Knots) as prior unit, it should also run with the other units.

- Bildschirmfoto 2020-12-17 um 09.46.24.png (79.5 KiB) Viewed 3666 times
don't forget to make a backup of the file before.. The little differences in the screenshots are due to different times of creating it.