Bureau of Meteorology


The BOM Blog gives you the background and insider info on weather, climate, oceans, water and space weather—as well as the latest on the work of the Bureau.


We welcome participation in the comments section of our blog; however, we are not able to respond to all comments and questions and your comments may take a little time to appear. The blog is monitored from 9 am to 5 pm Monday–Friday.

Our community includes people of all ages and backgrounds and we want this to be a safe and respectful environment for all. To keep the discussion interesting and relevant, please:

  • respect other people and their opinions;
  • keep your comments on topic and succinct;
  • say why you disagree or agree with someone;
  • comment constructively—in a way that adds value to the discussion.

When commenting, please don't:

  • make defamatory, libellous, false or misleading comments;
  • use obscene, insulting, racist, sexist or otherwise discriminatory or offensive language;
  • post personal information about yourself or others, such as private addresses or phone numbers;
  • promote commercial interests;
  • violate the intellectual property rights of others;
  • violate any laws or regulations;
  • provoke others, distort facts or misrepresent the views of others; or
  • post multiple versions of the same view or make excessive postings on a particular issue.

We won’t publish comments that are not in line with these standards. Blocking/removal of content or banning of users is at our discretion.

There is no endorsement, implied or otherwise, by the Bureau of any material in the comments section. Users are fully responsible for the content they submit.

Commenting is available via a Facebook plugin, which can only be accessed by those with Facebook accounts.

You can contact us at bomblog@bom.gov.au.

Copyright | Disclaimer | Privacy


Contact our social media team at socialmedia@bom.gov.au

Clearing up the ‘patchy rain’: introducing a more precise forecast language

Clearing up the ‘patchy rain’: introducing a more precise forecast language

Updated 24 August 2018

You probably read or hear the weather forecast almost every day, but what do all those terms actually mean? To make rain forecasts more helpful, we now use more precise language.

How many times have you read or heard on the radio that there’ll be scattered showers or patchy rain where you live or work? How much does this information really help you—especially if you’re about to hang out the washing, or are trying to decide whether to take an umbrella to the office?

As our weather information has become more detailed and precise, the language of our forecasts has followed suit. We changed the way we describe the likelihood of rain, to ensure that our forecast descriptions are as clear and precise as our graphical services. Forecasts now tell you if the chance of rain in your area is slight, medium, high or very high at different times of the day, with a percentage equivalent.

For example, here's a forecast for Sydney and the surrounding area:

Screenshot of forecast showing min and max temps, possible rainfall, chance of any rain and a forecast for the Sydney area

The left side of the forecast provides the temperatures, possible rainfall amounts and the chance of any rain for Sydney's city centre.

The right side elaborates on these figures with a statement such as a ‘High (70%) chance of showers’. Sounds like umbrella weather, doesn’t it?

Let’s explore this a bit further. ‘High’ relates to a simple scale of how likely you are to receive rainfall in that forecast area. This scale is shown in the table below:

Chance of rain

Terms used

0%, 10%

No mention of rainfall in forecast

20%, 30%

Slight (20%) chance of… Slight (30%) chance of…

40%, 50%, 60%

Medium (40%) chance of… Medium (50%) chance of…

Medium (60%) chance of…

70%, 80%

High (70%) chance of… High (80%) chance of…

90%, 100%

Very high (90%) chance of… Very high (near 100%) chance of…

This simple information is probably enough to tell you how likely you are to get wet and whether you need a raincoat. But what else can you tell from the forecast?

Timing of rainfall: If the chance of rain is confined to a short period of the day, you may see words such as ‘most likely in the morning’.

Heavy rainfall: If very heavy rainfall is a possibility, you may see words such as ‘Showers, heavy at times’. This one might be a useful warning to check that those gutters are clear.

Thunderstorms: If there is a chance of thunderstorms during the day, this will be mentioned.

Other weather: When appropriate you will also be advised of other weather phenomena, such as hail, frost, fog or snow.

So there you have it. This forecast language will help you make important decisions about your outdoor activities every day.

More information

Right as rain: how to interpret the daily rainfall forecast

Explainer: how is rain forecast?

BOM Blog. Click this banner to subscribe for the inside story on weather, climate, water and oceans.

Comment. Tell us what you think of this article.

Share. Tell others.