Here’s an excerpt from this excellent post that makes the case that Jesus was crucified on a Thursday, (because He spent 3 days and nights in the heart of the earth):

Additional Sabbath Days

There are a number of other Sabbaths in addition to the weekly Sabbath.  The word “sabbath” means rest and God declared rest for His people with weekly Sabbaths and additional Holy Days of Convocation.   Collectively, these Sabbaths are called “seasons” (Gen 1:14) or God’s appointed times (Leviticus 23:2), and they include:

Weekly Sabbaths:  52
Days of Passover:     7
Shavout, Feast of Weeks (Pentecost)  1
Yom Teruah (Feast of Trumpets)   1
Yom Kippur (Day of Atonement)    1
Days of Sukkot (Feast of Tabernacles)  1
Shimini Atzeret (8th Day of Assembly)   1
= 70 Sabbaths

The early church considered the reference to the Sabbath in Mark 15:42 to mean the weekly Sabbath. Since Jesus was crucified on the day of preparation, they assumed it to have taken place on Friday afternoon.  The error in this logic is that the Sabbath referred to in Mark 15 is the Feast of Unleavened Bread, one the seven Holy Days of Passover.

The Passover Sabbath

The Feast of Unleavened Bread is also known as the Feast of the Passover, which was celebrated in remembrance of the Israelites being delivered from Egyptian bondage.  This feast is set on Nisan 15 (Leviticus 23:6), which could fall on any day of the week.  This feast day is a High Sabbath (a day of rest), also called a High Day and it was preceded by a day of preparation.

John 19:31  Therefore, because it was the Preparation Day, that the bodies should not remain on the cross on the Sabbath (for that Sabbath was a high day), the Jews asked Pilate that their legs might be broken, and that they might be taken away.

John 19:31 tells that Jesus was crucified on the Preparation Day before the High Day Sabbath of the Feast of Unleavened Bread.  This places the date of Jesus’ crucifixion on Nisan 14.  Since the Passover feast is set according to the calendar (unlike the weekly Sabbath that is set according to the day) the question becomes, on what day of the week was the feast day that year?