Solar Electric Report for a Rainy Spring in Seattle

The Spring report is in… and it’s showing lower-than-expected solar electric production for the sunny side of the year.  Could this be caused by the almost record-breaking levels of rain during the month of April?

Solar electric production from March 22 through June 21 this year was 1,464.04 kWh (1.46 MWh).  This means an average of 15.91 kWh per day during this 92-day period — considerably less than the 24 kWh average daily production I had predicted in an earlier post.

SunnySideSample

The peak production day was 25.5 kWh on June 18.  The lowest day was April 27 with only 3.38 kWh of electricity produced.  Seattle got almost 6 inches of rain during the month of April — twice the recorded average for April, and just shy of breaking the recorded-history record of 6.53 inches.  Even the month of May had more rain than average.  The question is, what was June’s excuse?

Spring Solar Electric Production
A chart of solar electric production between March 22 and June 21, 2013.