Wondering when this year's brood of cicadas will emerge, and whether they will appear in your backyard? A Virginia company is helping answer the first of those questions.
The stubby, winged insects emerge when the soil reaches 64 degrees. Given a series of cold mornings in the middle of this month, the ground is still several degrees too cold for that, at least in Northern Virginia.
Sutron Corp., a Sterling, Va., company that specializes in environmental monitoring, has posted a "Cicada Tracker" website that plots the daily ground temperature.
The graph shows that the soil has remained in the 50s for most of this month, briefly flirting with 60 degrees around April 19 at Sutron's headquarters. But at about 55 degrees as of Wednesday, the ground will need to warm by 9 degrees before the cicadas start to stir.
Ground temperatures in Maryland are likely slightly cooler given that we are further north. The average temperature at Dulles International Airport in Northern Virginia has been 56.4 degrees so far in April, compared with 55.5 degrees at BWI Marshall Airport.
But cicadas are not expected to appear in large numbers around BWI or the Baltimore area. The brood slated to emerge next month was largely confined to Calvert and St. Mary's counties in Southern Maryland. There, the ground temperature could be more comparable to that of Northern Virginia.
Stay tuned to the Cicada Tracker as the weather warms, and start listening for their mating calls next month.