So we know that Augustus named a month for himself. But why the time period that we now designate August? This is like one of the worst times of year to be in Rome. Do we have any evidence from that time period that explains his rationale? Do we know if he considered a different time of year? Thanks!
We do have evidence from contemporary(?) writers that suggest that the month was renamed after Augustus because it was a successful month for him pretty much. The date of the change is often suggested as being within the year 27 BC due to comments by Livy (Periochae. 134). According to Macrobius, the month was changed with the act of the senate who renamed it in Augustus' honour.
Macrobius, Saturnalia. 1.12.35:
Next is August, previously called Sextilis until it was assigned as an honor to Augustus by the senate decree the words of which I have given below: 'Since in the month Sextilis Imperator Caesar Augustus entered his first consulship and led three triumphs into the city, and the legions brought down from Janiculum attached themselves to his auspices and good faith; and since in this month Egypt was brought under the dominion of the Roman people, and in this month the civil wars were brought to an end; since for these reasons this month is and has been most fortunate for this empire, it pelased the Senate that this month be called August.'
Suetonius. Augustus. 31.2:
He restored the calendar, reformed by Divus Iulius but afterward carelessly muddled, to its original order; in reforming it he gave his own cognomen to the month Sextilis, rather than to September the month of his birth, because it was in the former that he had won his first consulship and signal victories.
So, it was renamed August because it was a 'most fortunate' month for the Empire, and given Augustus' fondness of positive propaganda, it is no surprise he chose such a month.