King James Bible
"And it was at Jerusalem the feast of the dedication, and it was winter."
This feast, known as Hanukkah, commemorated the temple's rededication in 164 BC after Judas Maccabeus defeated the Greeks who had desecrated it. John situates Jesus at this celebration of Jewish independence and religious freedom, creating dramatic irony as the religious leaders will soon reject Him. The temporal detail (December) explains why Jesus teaches in Solomon's colonnade (v.23) rather than outdoors. The coldness of the season parallels the spiritual coldness Jesus encounters from His opponents, setting an atmospheric tone for the confrontation that follows.