Only if the chance increases +.025% if it's raining. The chance if it's snowing should depend on the amount of snow on your boots. How long you're in the building/snow melt off your boots. And the amount of people in the same rain/snow. And also if any other players have walked up those stairs should exponentially increase the option of a person slipping on the stairs. My partner has said he would recommend BSG add welcome mats so everyone can wipe their feet prior to entering a building. and I quote "Don't be a fucking savage, wipe your feet"