I think I have found a typo in the OWM-forecast.php script. It's on line 122 of the distributed file.
The code reads as follows:
// Units: Temp,Baro,Wind,Rain,Snow,Distance
// 'si' = C,hPa,m/s,mm,mm,km
// 'ca' = C,hPa,km/h,mm,mm,km
// 'uk' = C,mb,mph,mm,mm,km
// 'us' = F,inHg,mph,in,in,km
The last entry in the "us" line is the one in question. Since the US uses miles for distance and not kilometers, shouldn't this be "mi" or whatever designation is used to indicate miles?