Patchy frost is in the forecast for early Sunday morning and again early Monday morning. And while we are entering the middle of May, frost is not unheard-of this time of year.
In fact, the latest freezing temperature (32°) observed in Rockford over the current climatological period (1981-2010) is May 27th. Most climate observation sites across northern Illinois are similar, with the exception of Mount Carroll. Over the past thirty years, the latest freezing temperature observed in that Carroll County community was June 10th!
On average, the last 32° reading in Rockford is April 27th. It is interesting to note that in 2013, Rockford has not fallen to 32° since April 26th! But that could change, since temperatures are expected to fall into the lower 30s both Sunday and Monday morning. Climatologically speaking, the chance to see such chilly temperatures will continue to decline. Nine times out of ten, we won’t see temperatures fall below the freezing mark any later than May 14th. -Joe
This post was written by Joe Astolfi on May 11, 2013