As we've had to explain many times in the past that the internet does not exist in an impervious bubble, and that Google Adwords like any other type of business activity is affected by real world external factors; JohnH is also now very happy because finally he has some proof from the horses mouth how the weather impacts Google Adwords.

via the New York Times, interview with Hal R. Varian, chief economist at Google.

In mid-February, for instance, the group was taken aback when they saw the number of searches drop unexpectedly. With their antennas keenly tuned for any sign that the economic slowdown could be hitting Google’s business, members of the team rushed to come up with a diagnosis. That meant poring over statistics, calling field offices and checking data centers e to ensure none were afflicted by bugs.

The team determined that Google had suffered from a series of unrelated minor ailments. Mardi Gras and the Chinese New Year kept people away from their computers, while bad weather knocked out electricity in parts of China, Mr. Varian said.

Other events have given Google unexpected increases in traffic because they kept people at home, like heavy rains and flooding in England last summer and a strike in France last fall.

“Bad weather is good for Google, as long as it is not too bad,” Mr. Varian said.