For the rest of us, terms such as isolated showers, scattered showers, patchy rain and mostly fine can lead to a day of frustration as we put on and take off the layers and wet weather accessories.

But now the Bureau of Meteorology says it is moving to reduce the confusion of the language that it uses. By the end of this week, the terminology used throughout Australia for the chance of rain in forecasts will be based on a percentage figure.

A zero to 10 per cent chance of rain will not rate a mention in any forecast, 20 to 30 per cent will be referred to as a slight chance, 40 to 60 per cent will be a medium chance, 70 to 80 per cent (high chance) and 90 to 100 per cent (very high chance).

The Bureau's national manager of public weather Vernon Carr said it was hoped that the new terms would create more certainty for people's planning.

"The Bureau ... found that a lot of people don't quite understand the words like scattered, isolated (and) patchy so we've moved towards a more precise system that we will introduce this week," Mr Carr said.

"... Most people know that rain is a difficult thing to predict anyway. It could rain across the road and you'd stay dry, it's that difficult, that's why we used vague words in the past but with new technology and systems we can get a bit more specific about what was the chance of getting wet today."

Mr Carr said the Bureau's new Meteye system, which divides the nation into six-square-kilometre grids and allows for highly localised meteorological observations and forecasting within each square, had formed the basis for the more precise terms.

Mr Gell said the change was "probably 20 years overdue" but most people would not notice because they did not understand the basics of weather.

"It makes sense to use percentages because that's what most of the (mobile) apps utilise," Mr Gell said.

"There is still a fundamental problem that FM radio stations in particular [have], even if the forecast is for one or two showers, they'll say it's going to be a wet day because they don't even bother to understand what one or two showers mean so it's probably better to use this because people are lazy.

"... I doubt that people will notice. They'll still believe that they can determine what they're going to wear (based) on the temperature rather than understand the wind strength and the amount of sunshine."

However, he said changing a routine that had been established for decades could upset those who "loved weather" and for many years had a set way in which they recorded conditions.

"There are people who keep weather records for years and years and pass them down through families so no doubt their  day is going to get upset a bit," Mr Gell said.