A freeze watch is in effect for the Baltimore suburbs Friday night into Saturday, with temperatures potentially reaching the 20s or 30s.
The National Weather Service's Baltimore/Washington office issued the watch Thursday afternoon. The advisory cautions of a risk to unprotected vegetation vulnerable to freezing.
The watch is in effect in northern Baltimore County and Harford, Howard and Carroll counties. It extends further west to Montgomery, Frederick, Washington and Allegany counties.
Temperatures last reached freezing at BWI Marshall Airport on April 3, and last into the 20s March 11. Of course, being in Anne Arundel County, BWI is not included in the freeze watch so it may be a few more weeks before those marks are reached at the airport.
For much of the suburbs, a freeze at this point in the fall would be relatively rare. One year out of every three, on average, the first freeze doesn't arrive until Oct. 15 in Westminster and Oct. 17 in Frederick. In Bel Air, on the other hand, freezes come a bit earlier, with one by Oct. 10 one out of every three years and by Oct. 16 every other year, on average.
In Baltimore City and points south, first freeze comes before the end of October less than 10 percent of the time, with the typical date falling around mid-November. View the dates for where you live on this table the University of Maryland Extension keeps.