FPUS41 KBGM 200610 City Forecast for Penn Yan, NY Issued Thursday morning - Oct 20, 2005 .Thursday... Partly cloudy, high 55, 10% chance of precipitation. .Thursday night... Low 38, 10% chance of precipitation. .Friday... Sunny, high 53, 10% chance of precipitation. .Friday night... Low 37. .Saturday... High 53.