Volunteers have been observing and recording weather, climate and water data for the Bureau of Meteorology since 1908.
The network now includes weather observers, rainfall and river height observers, storm spotters and volunteers at sea.
While the BoM's observation network is extensive, there are many areas that are not covered except by the service of volunteers.
There are about 500 open volunteer rainfall stations in Victoria.
But they serve all of Australia by providing the Bureau with the high quality observations needed to make accurate forecasts.
The observations also help strengthen the understanding of flood control, irrigation, land use, drought, storms and climate change; they're also vital to many aspects of agriculture.
While the history of each site and volunteer is different, their dedication to the contribution of rainfall data and weather observations are uniform.
The standard manual rain gauge consists of a can and a 203 millimetre funnel, which channels the rain collected into a measuring cylinder.
It has been designed to minimise evaporation losses, can hold 25mm and any overflow is captured in the can for the observer to add to the total.
Daily rainfall is usually measured at 9am local time, recording the total for the previous 24 hours.
However, there are a number of sites which report 48 or 72 hour totals (or occasionally longer) over weekends if the observer is unable to be present.
Volunteer rainfall observers send in a monthly record of daily precipitation at the end of each month.
Observers at locations send their observations electronically to the BoM each day.
Prior to 1974, rainfall was measured to the nearest point (one hundredth of an inch).
Since then, most observations have been taken to the nearest 0.2mm.
Any moisture less than this is recorded as a trace.
It is a little-known fact that as a young boy aged 14, Gough Whitlam was, for a short while, one of the country's volunteer weather observers.
Victoria was the first state in Australia to engage volunteer observers and the strong tradition of this service continues.
The Bureau recognises and celebrates the outstanding achievements of its volunteers, offering excellence awards for 50 years of service to individuals and for 100 years of service to family volunteers.
- Jonathan Pollock is a climatologist with the Bureau of Meteorology