In our Spring access class, a student asked where biometrics are typically used outside? In my experience, finger/palm/iris readers were not a good option, but that may have changed.
For example, using fingerprint readers outside often required some sort of rain shield, even when the reader itself was rated for wet areas. Drops of rain/snow/dust/dirt negatively impacted performance if not used:
******* ** *********** ****** *** ** weather/sun/precipitation *** ************ **** ***** ******* to ***** *** ** *** *******, or ****** ****** ** ***** ** potentially ***** ********, ***** *** ********** a **** *** ********?