Jesus's corpse would've been identifiable simply by its location1 (Note: They knew were Jesus's tomb was.) This is relevant because it renders corpse decomposition irrelevant.
There would be a thoroughly sufficient combination of these durably recognizable features that would be dead giveaways that the corpse was Jesus's:
We know this for 3 kinds of reasons...
This is relevant because if corpse-decomposition is going to explain why Jesus's body was not examined and used to refute early Christianity, then there needs to be a relevant connection between its decomposition and that lack of refutation. This fails insofar as it hopes to be that relevant connection.
• It is reported that it was very cold.
• Robert Gundry: “…the high elevation of Jerusalem can make it cold at Passovertide. …” [Mark: A Commentary on His Apology for the Cross (Eerdmans, 2000), 997.]
• Raymond Brown: "Actually, it can be quite cool in mountainous Jerusalem in early spring;” [The Gospel according to John XII-XXI (Doubleday, 1970), 982.]
• William Lane Craig: “Jerusalem, being 700 meters above sea level, can be quite cool in April.” [Assessing the New Testament Evidence for the Historicity of the Resurrection of Jesus (Edwin Mellen, 1989) 204.]
• Jn 18:15-18, 25 -- “[Just before Jesus' crucifixion, one disciple] entered with Jesus into the court of the high priest,... Now the slaves and the officers were standing there, having made a charcoal fire, for it was cold and they were warming themselves; and Peter was also with them, standing and warming himself. …, Simon Peter was standing and warming himself.”Regarding humidity, it would have been arid.
• Gary Habermas & Michael Licona: “…in the arid climate of Jerusalem, a corpse's hair, stature, and distinctive wounds would have been identifiable, even after fifty days (This information was obtained from the Medical Examiner's Office for the Commonwealth of Virginia. The physician in charge said that even in Virginia, which has a climate warm and damp enough to promote quick decomposition, an unprepared corpse undergoing a normal rate of decomposition should still after fifty days have its hair and an identifying stature. The wounds would “definitely” be identifiable. Thus, a corpse in a much worse state than what would be expected for arid Jerusalem would still be identifiable after fifty days.).” [The Case for the Resurrection of Jesus (Kregal Pub., 2004), 70-71.]For an example that brings home the relevance of this: the corpse of Medger Evers was found 30+ years after death, and remained well preserved for this reason. See Christine Quigley, Modern Mummies (McFarland, 1998), 213-214.