Applicators need to be able to anticipate the changes in temperature, humidity, wind speed and wind direction that normally occur at different times during the day and night, known as the diurnal variation, as well as the seasonal changes to the diurnal variation that may occur at their location.

Accessing reliable weather forecast information is essential for planning spraying activities. The general Bureau of Meteorology forecast for inland areas of Australia has traditionally been based on a 25km2 area, whereas the coastal forecasts and certain other areas tend to be a little more specific, based on a 12km2 forecast area. However, this situation is rapidly changing as access to improved models becomes available. Spray applicators should always confirm the accuracy of the weather forecast for their location against measurements at the site of application.

While the available scale of the forecast area may be reasonable in many districts, in others there may be local variations in wind direction and wind speed due to landscape features. These differences need to be evaluated to determine the accuracy of the forecast at various locations, before relying on the information provided.

The WAND and COtL networks provide more detailed, localised and real-time information to assist spraying decision where there is a base station in appropriate proximity to the application site.

Weather forecast information should always be regarded as a planning tool, it is not a substitute for measuring and recording the weather conditions at the site of application.

Examples of weather forecasting websites for agriculture

There are a number of free services, such as those provided by the BoM, as well as some subscription-based services that utilise some or all of the same models that the BoM uses.

Some of the subscription services reduce the forecast area to areas as small as 1km2, which can greatly improve the forecast accuracy for an individual farm, or for several farms.

Free Services

• BOM MetEye. This service can provide forecasts based on your latitude and longitude, with wind speed and direction forecasts provided at 3-hourly intervals.

• Another free forecasting service, provided by Syngenta, the Syngenta Weather site which provides hourly forecasts to 5 days in advance, specific to the location.

Find out more

For more information about Agricast, go to www.syngenta. com.au/weather

Many subscription-based services charge a monthly or annual fee for access, but for this price they tend to provide additional services, or an increased level of forecast accuracy for specific locations.

Before signing up to a particular service, if they offer a free trial period take advantage of this to check the accuracy of the forecast for the locations where you conduct spraying activities.

Use the trial period to regularly measure the conditions at your location and compare these to the forecast provided. During the trial period, it is worthwhile comparing various forecasting services with each other and with the free services to determine if you gain a better forecast for your location.

Some of the subscription-based services, such as Nufarm SprayWise®Decisions, provide indications of suitable conditions for spraying by highlighting parameters such as wind speed, Delta T and inversion risk

Find out more

For more information about the SprayWise Decisions website, visit: SprayWise Decision Making Tool