OK, this much is certain: Spring will arrive in March, which begins at midnight tonight. The Vernal Equinox arrives at 1:25 p.m. on Monday, March 20, and winter, officially, will end. Bulbs will flower, trees will bud, grass will green. It's a simple matter of celestial mechanics. But March can be cruel. More on that in a minute.

The good news is that average daytime highs in March climb from 49 degrees at the start of the month, to 59 degrees by the end. Overnight lows slip back up and over the freezing mark, from 29 degrees to 38.

It can get downright hot. Record highs in March have reached the 80s, and even 90 degrees on a single date - Mar. 29, 1945. The record lows range from 5 degrees on Mar. 4, 1873, to 21 degrees on several dates.

On the other hand (and there's always another hand), it can snow in March. In fact, it has snowed on every date in March, in Baltimore, since they started keeping track here in 1883. The average snowfall for March in Baltimore is just 2.4 inches. But there have been some serious exceptions.

The snowiest March day was on Palm Sunday, Mar. 29, 1942, when astonished Baltimoreans found 22 inches of snow on the ground, and the city at a halt. Here's the Weather Service account:

"The Palm Sunday Snowstorm dumped the state's heaviest March snow on record in Maryland. The storm began as rain but changed over to a wet heavy snow. The snow stuck to power lines, trees and shrubs damaging them under its weight. Many of the fruit trees had begun to blossom. Over 20 inches fell over northern Anne Arundel, Howard, Southern and western Baltimore County, Carroll County, eastern and northern Frederick County, and north-central Washington County.

"Maximum amounts reported were 31 inches at Clear Springs (just 12 days earlier the temperature had reached 79 F here), 32 inches at Westminster, 30 to 36 inches at State Sanatorium (Frederick County) and 36 inches at Edgemont (Washington County). Baltimore City received its greatest snow in 20 years with 22 inches measured. Hagerstown and Westminster reported 22 inches in 24 hours. Frederick had 17 inches in 24 hours. Washington, DC received a total of 11.5 inches of snow."

Baltimore has seen snowfalls of 10 inches or more on five other dates in Marches past. The most recent March snowstorms to set daily records in Baltimore were on Mar. 30, 2003 (2.6"), Mar. 31, 1997 (1.4") and Mar. 13, 1993 (11.3").

Could it happen again this year?  Well, there have been just two entirely snow-free Marches since 1945.