One of the issues with monsoon season precipitation amounts is that strong, localized thunderstorms can produce large amounts of rain over a limited area. This means that a given rainfall measurement may not apply to a broader area. One of my friends challenged me about the National Weather Service’s July precipitation amount as measured at the Flagstaff Airport. They reported a total of 2.77 inches of precipitation. They note that it was the 50th wettest July since 1898. They also note that July was the 12th coolest on record, too.
So, I gave rainlog.org a look. Rainlog.org is run by the University of Arizona. They collect rainfall data from people that have rain gauges. It is completely self-reported and not audited. I routinely reported my observations to rainlog.org while I was measuring it. If anything, I think the rainfall reports would be underestimated because of forgetfulness. Below is what I found. I think 2.77 is reasonable. However, as expected, the amount is not representative of the greater Flagstaff area. The downtown area, east Flagstaff and the areas east of the San Francisco Peaks were drier. Mountainaire and Kachina Village were wetter. I think many of us have accused the National Weather Service taking their rain gauge inside during storms so that it won’t get wet. Their July data looks good.