Bill Wade, Post-Gazette Charles "Mac" McCormick moves potted lilies ready for Easter into the greenhouse at Sestili Nursery on Swinburne Street in Oakland yesterday. The nursery supplies many churches, with the big Easter delivery days being tomorrow and Saturday. With the weather turning colder, Chuck Beck of Sestili's says it is best to use burlap and not plastic (which causes too much warmth) to cover your plants.

Most draw the line at 40, it seems.

At that temperature, winter borders spring. Gray borders green.

And, when temperatures plummet below that line -- as happened last night, exactly two weeks after the start of spring -- the dissonant chill interferes with plans. Especially leading into a weekend when some Easter services are held outdoors, baseball season hits its stride and television networks give us an entire golf tournament's worth of blooming azalea camera shots.

Because of yesterday's sudden temperature drop, Pittsburgh will spend spring's pre-eminent weekend still mired in winter.

Temperatures, which began in the morning close to 60, slid to Frigidaire levels by nightfall: first 40s, then 30s. The National Weather Service predicts that temperatures tonight could dip into the low 20s. Snow accumulation is unlikely, although the potential for snow flurries will linger into the weekend.

That means outdoor sunrise services planned for Easter will move indoors. (At Mount Nebo Presbyterian Church, 40 degrees is the cut-off.)

That means high school baseball teams, with coaches already tired of indoor practices, head with reluctance back to the cramped gyms.

"If it's anything below 40, practicing outside does more harm than good," Hopewell baseball coach Joe Colella said. "Kids are uncomfortable. They really can't focus."

Wild swings typify Pittsburgh's April weather, of course. For April 5, the record high is 83 degrees; the record low is 17. And, no, those didn't occur in the same year.

"There's a lot of variation in this time of year," said Terry Parrish, meteorologist at the National Weather Service office in Moon. "In the dead of winter, it will be cold -- you know it. In the dead of summer, it will be hot.

"But during transition times, as we call this, you can swing real rapidly, and that's what we're doing right now."

Only on Tuesday, Mr. Parrish said, will temperatures likely return above 50 degrees.

Until then, Pittsburghers will deal with the repercussions of winter redux.

Shaler Area High School's baseball team is scheduled today to play Bethel Park -- a game already rescheduled once. Though Shaler's players are equipped with specialized cold-weather gear, sweats, winter caps and batting gloves, the odds for injury increase when weather turns wintry, head coach Bob Hinds said.

And, as a result, his team probably won't play today.

Hopewell began its informal workouts in early January in the school's alternate, smaller gym. Players used rubberized balls. They tried to work on the fundamentals -- with soft toss and infield drills -- but really, they waited: Nothing can replicate a ground ball on a dirt infield.

"Weather makes baseball a job or makes it pleasurable," Mr. Colella said. "Nice day, it's great to go out there. If not, it's a chore."

In part because of the weather uncertainties, few churches in the region hold Easter services outdoors.

Before Washington Alliance Church officially moved into its new building, Pastor C.D. Croscutt thought about reinstating the al fresco proceeding. But then, he noticed two problems. The outdoor landscaping wasn't quite ready. Nor, as it turned out, was Mother Nature.

"We'll have it indoors," Pastor Croscutt said. "The weather kind of solidified our thoughts on that."