Rights: University of Waikato Published 3 November 2009 Download



Relative humidity is the amount of water vapour that the air can hold. A low relative humidity means that the air is getting very dry, and fuels will start to lose moisture, they will become drier as well. And then when they become dry, that is when they are prone or susceptible to being ignited and fires starting. So generally, the drier the air becomes, the lower the relative humidity, that is when the fire risk or the fire danger will start to increase.