THE SEASONAL NATURE OF WEATHER FORECAST ACCURACY

Fall is in the air, the leaves are turning, and we had snow at the office today! The season is definitely changing. Weather forecast accuracy changes with the seasons as well. In the summer, high and low temperature forecast accuracy gets better, and in the winter, it gets worse. This is true even for areas that don't have much seasonal change, like Florida (http://www.forecastadvisor.com/browse/Florida).

I talk about this more in this blog posting: http://www.forecastadvisor.com/blog/2006/09/wall-street-journal-online-article.html

THE NUMBERS GUY TALKS ABOUT FORECASTADVISOR

"The Numbers Guy" is a column in the Wall Street Journal Online written by Carl Bialik. He writes some very interesting stuff about how numbers are used (and abused) in print, on the web, and in public. You can catch his articles for free here (http://www.wsj.com/numbersguy), and you can catch the article about ForecastAdvisor, called "Grading Weather Forecasts", here: http://online.wsj.com/public/article/SB115816640287562053.html

This article resulted in additional mentions, in LifeHacker (http://www.lifehacker.com), WRAL's Tech Talk (http://html.wral.com/sh/blogger/wraltechtalk.html), Kim Komando (http://www.komando.com/), Kottke (http://www.kottke.org), and more. Thanks to everyone for their interest and kind words! And thanks to everyone who has written with ideas and suggestions. We strive to make ForecastWatch and ForecastAdvisor as educational and useful as possible.

SEPTEMBER 2006 DATA LOADED

We've audited and loaded the September 2006 accuracy data into both ForecastWatch (http://www.forecastwatch.com) and ForecastAdvisor (http://www.forecastadvisor.com). Temperature accuracy is beginning its seasonal dip. Overall high temperature error was at its lowest in July, at 4.05 degrees error. In August it started moving back up to a peak in mid-winter. September continued the trend. Overall high temperature error in September was 4.57 degrees.

One interesting thing to note is that it was a very cool September. ForecastWatch tracks how an unskilled climate forecast compares to weather forecasts by the weather forecast providers. But this also tells us how the climate is doing, because all we are doing is comparing climate normals with what actually happened. In September, for the about 800 observations locations we track, high temperatures were 2.33 degrees below 1971-2000 climate normals. Low temperatures, on the other hand, were only 0.14 degrees below normal. The National Climatic Data Center has said that September was the 31st coolest on record.

You can read more about September temperatures here: http://www.forecastadvisor.com/blog/2006/10/very-cool-september.html

Please let us know what you think at ideas@forecastwatch.com . We welcome your ideas and suggestions to make our services better and more useful.

3. Copyright 2006 Intellovations, LLC.