Sarah Maury Swan writes from Granite: "March is known for having heavy winds, especially at the beginning of the month. Why is that? Changes in Earth temperature?" Yes. Blame spring. The year is still young enough to bring us cold, clear, Arctic high pressure. But higher sun angles to our south are firing up storms (low-pressure systems). They're pressing north, creating steep pressure differences against the highs. That's what fuels strong winds. March is Baltimore's windiest month, averaging 10.5 mph at BWI.