Christian Calendar
Updated 16 Feb 2021

The Christian calendar (also known as the liturgical calendar or ecclesiastical calendar) is an annual schedule that commemorates certain days and seasons related to the history of salvation. Some denominations—including Anglicans, Lutherans, Methodists, and Presbyterians—observe most of the traditional calendar, while other denominations—including Baptists and most nondenominational evangelical congregations—tend to focus on only a few dates, such as Christmas and Easter.

January
Twelfth Night Jan 6 - A festival in some branches of Christianity
 marking the coming of the Epiphany and concluding the Twelve Days of Christmas.
 Epiphany - (Koine Greek: , epiphaneia, "manifestation", "striking appearance"
 Close of christmastide - Jan 6 (Feast of Epiphany)- to the beginning of Lent
 Greek for "manifestation," "show," "revealed."
 Focus on God manifesting as Jesus
  
Western Christians commemorate principally (but not solely) the visit of the
 Magi to the Baby Jesus, and thus Jesus' physical manifestation to the Gentiles,
  The Sunday occurring between 2 and 8 January.
  - 
February or March 
  Lent - 40 days before Easter
   (based on the 40 days of temptation that Jesus faced in the wilderness) 
March or April
 Easter - Sunday following the 14th day of the lunar month 
   Can occur from March 22 to April 25
  Holy week - Week before Christmas - From Palm Sunday to Holy Saturday

  Palm Sunday (when Jesus triumphantly rode into Jerusalem on the back of a donkey)

  Maunday Thursday - Commerates the Last Supper - Jesus passover meal with the Disciples 
     Comes from Washing of the Feet (Maundy) 

  Good Friday - Crucifixion
      Tenebrae service is to recreate the emotional aspects
 of the passion story (crucifixion). Candles are extinguished one by one until
 the Sanctuary is in total darkness. This increasing darkness symbolizes the
 approaching darkness of Jesus' death.

  Holy Saturday - Easter Vigil
  (when Jesus was buried after his passion and crucifixion on Good Friday).

  Easter Sunday - Celebrate the resurrection
April
  Easter Season - 50 days following Easter
May

June Pentecost - 50th Day after Easter Celebrates the occasion of the Holy Spirit first descending upon Christ’s disciples. November Advent - Latin for "coming" - Sunday that falls nearest Nov. 30 Four Sundays before Christmas December 25 Christmas Christmas season lasts the 12 days from Dec. 25 to the Feast of the Epiphany on Jan. 6.

Links:
9 Things You Should Know About the Christian Calendar | The Gospel Coalition
2020 Christian Calendar – Christian Religious Festival Calendar 2020
The Christian Calendar | Word of Life Church