Summer squash and tracking first and last frost for my farm

We had a frost two days ago.  I think it is the last so I put out my summer squash under floating row cover.  I have been tracking first and last frost for my farm pretty methodically for the past 10 years.  I keep a journal by my bedside and while I drink my morning coffee I write down the weather and main activities from the previous day.  I try to zero in on first and last frost because they affect when to plant and harvest so dramatically.  For my farm I can get a frost as late as May 7th, but the last frost can be as early as April 18th.  The most often date or mean is May 1st.  I can expect a first frost as early as September 22 or as late as November 8th but most likely around October 12th. Jess took these beautiful photos of the frost: