How Wrong is the Weather Forecast?

Posted by on Thursday, September 10, 2015
If you were to ask someone "what is one job you can have where you can be wrong half the time and still have that job?" Chances are the answer would be a meteorologist.

For meteorologists and forecasters alike, having thick skin is something that you need in that profession.

But how wrong is the weather forecast?

The short answer is that really it depends on how you look at it. A large part of the problem is simply a lot of people don't understand the forecast.

Lets take this example:

"Today - A mix of Sun and Cloud. 40 percent chance of showers this afternoon. Wind north 20 km/h gusting to 40 km/h. High 22."

So stop for a second and think, how do you interpret that forecast?

Ok now lets describe what it means. Generally speaking "Today" refers to 6 am to 6 pm. So the forecast is for that time frame. So today the forecast area will see both sunny and cloudy skies. However there is a 40 percent chance of showers falling somewhere over the forecast area (not necessarily your house) between 12 noon and 6 pm. Wind north 20 km/h gusting to 40 km/h means that wind will be coming from the north (not the opposite). The wind will be sustained at 20 km/h with some gusts to 40 km/h.

Finally the daytime high. Normally the daytime high occurs in the middle of the day when the sun is directly overhead. However factors such as a cold front can make the daytime high occur in the early morning for example. After which the temperature would fall. So when you see a daytime high of 22 degrees it means the average high temperature over the forecast area. The temperature may be higher or lower at your house. Also where you put your thermometer can give you a false reading. Never put it in direct sunlight. It should be placed a meter above the ground, in the shade and not attached to a structure such as a house or shed.

So in closing, short term forecasts and more accurate than long term forecasts, and posting 140 characters isn't a forecast. it takes a lot more than that to accurately get information across.

The Team

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