Belmar, NJ Hourly Weather | AccuWeather 63° RealFeel® 58° 68% Rain alerts Areal Flood Watch 12:00 AM Friday - 6:00 AM Saturday alerts Coastal Flood Advisory 6:00 PM Thursday - 2:00 PM. Be prepared with the most accurate 10-day forecast for Green Brook, NJ with highs, lows, chance of precipitation from The Weather Channel and Weather.com. Find the most current and reliable 14 day weather forecasts, storm alerts, reports and information for Belmar, NJ, US with The Weather Network.