A Fire Weather Watch is issued by the National Weather Service when the agency sees critical fire weather conditions that could increase a fire’s spread and growth if a fire were to occur. Michelle Mead, the meteorologist in charge at the National Weather Service in Sacramento, said a Fire Weather Watch also means officials are keeping an eye on those critical fire weather conditions to see if a warning needs to be issued.
The main conditions meteorologists look for when issuing a watch or warning, Mead said, are strong winds of at least 20 to 25 mph per hour with gusts over 35 mph and low relative humidity in the teens to single digits.
“So the stronger the winds and the drier the humidity, the higher potential for rapid fire growth for any fire that does spark,” Mead said.
The difference between a Fire Weather Watch and Red Flag Warning mainly has to do with how well the National Weather Service knows the timing of the critical fire weather conditions that are predicted to occur.
“The stronger the winds and the drier the humidity, the higher potential for rapid fire growth for any fire that does spark,”Michelle Mead, Meteorologist In Charge, NWS Sacramento
With a Fire Weather Watch, conditions are expected to occur within a given three-day period. A Red Flag Warning has a more focused timeframe with conditions expected to occur within 24 hours.
One important thing to remember when a watch or warning is issued, Mead said, is to make sure you know either actually takes effect, as they’re usually announced ahead of when they occur. Also, Red Flag Warnings that go into effect in the evening or overnight should be given special attention, she said.

“Those are the days that we would definitely recommend that you sleep with your cell phone next to your bed versus down in your kitchen,” Mead said. “Because if a fire were to break out, that’s when the emergency manager or the sheriff would say ‘hey, we need to get an evacuation alert out’ and that’s when the Wireless Emergency Alert would be utilized with a fire warning and/or evacuation warning.”
Wireless Emergency Alerts (WEA) are part of the national public safety system. According to the Federal Communications Commission (FCC), WEA notifications are geographically targeted and received by compatible cell phones and mobile devices. Unlike many other types of emergency alerts, Mead said WEA notifications push through a cell phone to sound an alert regardless of its users' silence settings.
“WEA is meant to bypass all of your ‘Do Not Disturb’ or sleep modes to alert you,” Mead said.
Not all cell phone and mobile devices can receive WEA notifications, so the FCC recommends you check with your wireless service provider to see if your phone or device is compatible.
Many counties in the North State also use other opt-in mobile alert systems to notify residents of emergencies, but they require residents to sign-up. Most of these do not push through a phone or device’s silence settings so be sure to understand your county’s system before depending on it for an emergency notification through the night.

You can use this map to keep track of Fire Weather Watches and Red Flag Warnings issued in California by the National Weather Service.