FPUS42 KMFL 182108 City Forecast for West Palm Beach, FL Issued Wednesday afternoon - Sep 18, 2019 .Wednesday night... Low 77, 20% chance of precipitation. .Thursday... Partly cloudy, high 86, 40% chance of precipitation. .Thursday night... Low 78, 40% chance of precipitation. .Friday... Partly cloudy, high 87. .Friday night... Low 76.