Mariton: Precipitation Rates

March 2, 2012

By Tim Burris, Mariton Preserve Manager

Both January and February had below average precipitation.  You might say that this was the dropping shoe that I had been awaiting.  After such a wet 2011, I expected things to get dryer eventually.  How much drier, we will have to wait to see. 

January ended with 2.89 inches (3.40″ is average).  In February, we received 1.32 inches (3.04″ is average).  Technically, we are around 2 inches below average for the year.  However, you have to remember that we ended 2011 with 25 inches above average.  The water table is still high, and a heavy rain will cause the springs on the hill to start gushing.

While weather watchers often talk about precipitation averaging out over a 6 or 12 month period, there are long term trends that also have to be considered.  When I first started collecting rainfall data at Mariton, the average annual precipitation was around 44 inches.  Then we had a couple years with rainfall in the 60+ inch range.  After that, we cruised along for several years with yearly totals in the mid 50 inch range.  Of course, last year that took a huge jump with over 80 inches of precipitation, but it only bumped my average less than 2 inches (to 53.54).  We could theoretically drop back to a 44 inch year without being in a drought (depending on the timing of the precipitation), and still remain within the normal range of rainfall.