Canadian high pressure will build into the mid Mississippi River Valley this evening, allowing winds to weaken over our area through the night. Under clear skies, we should see lows Monday morning ranging from around 40 in the metro areas to the lower/mid 30s across much of the rest of the region (see image below).
With areas of frost expected to develop, you should consider taking action to protect cold-sensitive plants.
How unusual is this late cool spell? High temperatures today will be roughly 15 degrees below normal, whereas lows tonight will be 15-20 degrees below normal. Over the last 30 springs, the average last date for Louisville to hit 40 or below has been April 28th, with the latest "last date" being May 22nd, back in 2002.