It is not enough to have vegetation; it must be dry enough to burn. The dryness switch represents the fuel moisture of dead and live plant material. There are many different ways to measure this. A simple one is vapour pressure deficit, which is connected to relative humidity and represents the atmosphere’s ‘thirst’ for water.
This data is based on vapour pressure deficit (VPD) measurements available from Australian Gridded Climate Data
To learn more about dryness as a driver of fire read: Major fires an increasing risk as the air gets thirstier, research shows
This data shows us the average dryness conditions across Victoria. Higher values represent greater fuel dryness (i.e. lower fuel moisture). The dryness shown here is a function of temperature and humidity. Conditions are more extreme in the hotter, drier northwest of the state. Maps show the spatial pattern of dryness. Graphs show the pattern of dryness over time for different regions, including annual, monthly and seasonal time scales. Although dryness records are available for earlier years, for maps we start in 2000 to allow comparison with other drivers and fire data. In the Graph section we go back to 1973 to allow comparison with long-term fire weather records. We use a fire year rather than a calendar year e.g. the 2020 fire year runs from July 2019 to June 2020.
Hover over the map and graphs to get more info. Click on the range to see changes between years.