August 24, 79 AD, the date traditionally associated with the eruption and pyroclastic avalanche that devastated Pompeii, is recorded in Pliny the Younger's account. However, it is possible that this date is the result of a transcription error that occurred during the Middle Ages, a time when confusion of Roman numerals was common. Therefore, some experts suggest that, in reality, the eruption could have occurred in autumn or winter, based on the presence of a large amount of autumn fruits among the ruins and the finding of a coin in a lady's purse whose mint date would have been no earlier than September 79. Some bodies also show thick clothing, suitable for colder weather, although this is not a definitive indication of the season of the year.

In 2018, a team of archaeologists discovered an inscription dated sixteen days before the November kalends in the ancient Roman calendar, which corresponds to October 17. According to this theory, the eruption would have taken place on October 24.