Fire Weather Watch/Red Flag Warning Criteria

Fire Weather Watches/Red Flag Warnings (RFWs) are issued when the combination of dry fuels and weather conditions support extreme fire danger and/or fire behavior. These conditions alert land management agencies to the potential for widespread new ignitions or control problems with existing fires, both of which could pose a threat to life and property.

The issuance of a Red Flag Warning does not predict nor guarantee new fire ignitions. It warns that predicted fuel and weather conditions are conducive for new ignitions and control problems with existing fires. Additionally, the lack of a Red Flag Warning does not mean that wildfire risk is not present. Very large wildfires can and do occur outside of Red Flag conditions.

A Red Flag event will be triggered for mainly leeward portions of the state when all three of the following criteria are met:

Keetch-Byram Drought Index (KBDI) ≥ 500 at specific stations and/or consultation with fire agencies
Relative Humidity (RH) ≤ 45 % at specific stations for 2 or more hours
Wind ≥ 26 mph (sustained wind, not wind gusts) at specific stations for 2 or more hours

RFWs will be issued on an island-by-island basis. The following stations will be used for wind, relative humidity, and Keetch-Byram Drought Index diagnosis:

Island	Wind	RH	KBDI	Eligible?
Kauai	Port Allen	Waimea Heights and/or Mana	Waimea Heights and/or Mana	No (updated 8/20/26)
Oahu	Bellows and/or Honolulu Airport	Honolulu Airport and/or Waianae Valley	Honolulu Airport	No (updated 8/20/26)
Molokai	Molokai Airport and/or Makapulapai	Molokai Airport and/or Makapulapai	Makapulapai	No (updated 8/20/26)
Lanai	Lanai1	Lanai1	Lanai1	No (updated 8/20/26)
Maui	Kahului Airport	Kahului Airport and/or Kealia Pond	Kealia Pond	No (updated 8/20/26)
Big Island	Kealakomo and/or Waikoloa	Kohala Ranch, and/or Waikoloa, and/or Kealakomo	Kohala Ranch and/or Waikoloa	No (updated 8/20/26)

Note that "Eligible" means that KBDI values are high enough and/or fire agencies have indicated that conditions are dry enough to warrant RFWs if the wind and RH criteria are met.