The journey to Jerusalem is said to have started on the first day of the first month, which would correspond with April 8, 458/457 BC. The fifth month would be August. The journey to Jerusalem thus took less than four months and it started on the same date as the original exodus from Egypt (Exodus 12:2; Numbers 33:3). The inclusion of these details is probably aimed at showing that the return of exiles from Babylon was something of a second exodus (Isaiah 11:11–16).1
9 For on the first day of the first month he began to go up from Babylonia, and on the first day of the fifth month he came to Jerusalem, for the good hand of his God was on him.