FPUS41 KOKX 041911 City Forecast for Westhampton Beach, NY Issued Wednesday afternoon - May 4, 2011 .Wednesday night... Low 40, 20% chance of precipitation. .Thursday... Mostly cloudy, high 59, 20% chance of precipitation. .Thursday night... Low 37, 10% chance of precipitation. .Friday... Sunny, high 64. .Friday night... Low 44.