Fallbrook, CA, United States 10-Day Weather Forecast - The Weather Channel | Weather.com 10 Day Weather - Fallbrook, CA, United States As of 20:30 PDT Tonight --/ 11° 11%. Today’s and tonight’s Fallbrook, CA weather forecast, weather conditions and Doppler radar from The Weather Channel and Weather.com. Find the most current and reliable 14 day weather forecasts, storm alerts, reports and information for Fallbrook, CA, US with The Weather Network.