As the physical seasons begin to evolve from spring to summer, many churches observe the changing spiritual season in which Easter rituals have passed.

Although not yet Christmas, many Christians arrived at church Sunday wearing red. The color, which symbolizes the Holy Spirit, is worn in observance of Pentecost, known as the birth of the Christian church.

"Traditionally (red) has been associated with the Holy Spirit," said the Vicar Scott Schul of Trinity Lutheran Church on Sunset Drive.

"Whenever the spirit arises it often appears as if it's a flame within the Bible."

Although void of fanfare and gift-giving, Schul said for many churches, the festival of the Pentecost is one of the three big festivals along with Christmas and Easter.

The concept relates to the second chapter of Acts, in which the Holy Spirit descends upon the disciples of Christ.

"Everybody could hear the words the apostle Peter was preaching and could hear it in their own language," Schul explained.

As with many churches, Trinity's Pentecost service related to the book of Acts, and red altar colors replaced the white paraments used throughout Easter.

The same was true at White Oak Springs Presbyterian Church in Renfrew.

"It's the one Sunday (when) I wear a red stole around my neck," said the Rev. Lee Dryer, explaining red cloth also distinguishes the communion table.

"The Christmas color is purple and Easter season is white. Most of the rest of the year it's green," he said.

"A few of the women will wear bright red jackets. I don't have red clothing, so I wear a red tie. Some people might wear a red carnation or something like that. Some of the guys will wear red socks. It's the one Sunday of the year where the liturgical color is red."

Although some churches opt to hold confirmation ceremonies in conjunction with Pentecost, others, like White Oak Springs, do not. But the 100-member church does hold a potluck to mark the occasion.

For Eastern Orthodox churches, Pentecost is observed over a period of days.

At St. Andrew Orthodox Church in Lyndora, the observance began on Saturday, when freshly cut greenery was used to adorn the interior and exterior of the church.

"The purpose behind that is to remind of us of God's creation and the beauty of Pentecost," said the Rev. Joseph Wargo of St. Andrew.

Orthodox priests also change from white vestments to green.

In Orthodox churches like St. Andrew, Pentecost begins with an all-night vigil followed by Pentecost Sunday, when priests say kneeling prayers.

"They're called kneeling prayers because we don't kneel from Easter until Pentecost," Wargo said, explaining standing depicts a theme of resurrection.

"We will stand during the (Pentecost) service, and at the end we all kneel down, and I pray the three kneeling prayers. That permits us to kneel again."

Known as Holy Spirit Day, Monday commemorated the Holy Trinity. Some churches had liturgy, with many of Wargo's parishioners attending a service at the Orthodox monetary in Ellwood City.

Although the fresh greenery will be removed by the week's end, the green vestments will remain, symbolizing new life and the birthday of the church.

"We go back into the cycle again," Wargo said.