Now there were in the same country shepherds living out in the fields, keeping watch over their flock by night.
One commentary states, “As these shepherds had not yet brought home their flocks, it is a presumptive argument that October had not yet commenced, and that, consequently, our Lord was not born on the 25th of December, when no flocks were out in the fields. On this very ground the nativity in December should be given up” (Adam Clarke’s Commentary, note on Luke 2:8).
The Interpreter’s One-Volume Commentary agrees: “These humble pastoral folk are out in the field at night with their flock—a feature of the story which would argue against the birth (of Christ) occurring on Dec. 25 since the weather would not have permitted it” (1971, note on Luke 2:4-7).
For more about why Jesus Christ’s birth could not have been Dec. 25 and how it came to be celebrated that day, see our article “Christmas: Should Christians Celebrate It?”