robzilla - 11:06 am on May 5, 2011 (gmt 0)
Note that the load times reported are not based on Googlebot's visits, but your visitors' (using the Google toolbar with PageRank enabled). That's why they fluctuate so much. Say your server is located in Europe, but most of your visitors are from the United States, then the average load time will be higher than if they'd also be in Europe. And the fewer visitors you have, the fewer data points Google will have to display an "accurate" average load time.
More info here: [google.com...]