A Dry Spell

I've been tracking the rainfall at our house for the last 5 years. I started collecting the data during the Master Naturalist class I took in order to obtain state certification in the program. The data collection is part of our chapter's Rainfall Monitoring Project.

The project divides Hays County in 30 sections, each about six miles wide and seven miles high. Participants report their monthly rainfall and their data is averaged with others in their section and graphed monthly. The project has data back to March 2005. The data will allow us to determine the average rainfall across the county and to see if there are any geographical differences.

You can find the project's results at the link above.

The charts below are the data at our house. The data starts in May 2007 and goes through May 2011. You can see how variable the monthly rainfall is. The annual totals are:

2007 - 28.2 (incomplete)
2008 - 16.4
2009 - 36.7
2010 - 43.1

2011 - 6.9 (so far)

In general, 2007 was a wet year, followed by a dry 2008. 2009 was average and 2010 was wet again. So far 2011 has been dry. The summers tend to be dry, but in July 2007 we had a house record of 12.7 inches.

The data is interesting to me because of my interest in the local habitat. It also affects us directly since rainwater is our house's main water supply. Texas is almost entirely in drought right now. You can view the U.S. Drought Monitor's most recent data here.

I've heard it said that the local rainfall average is 33 inches per year, with most years below average! These graphs may give you an idea of what that means.