The Jewish historian Josephus records that the Jordan River swells in winter, making it harder to cross (see War 4.7.5). Muddy roads also made travel difficult in winter.
Jews usually did not travel on the Sabbath, so that they could rest as God commanded (see Genesis 2:1–3; Exodus 20:8–11; 23:12; 31:12–17; Leviticus 23:3; Deuteronomy 5:12–15; Jeremiah 17:19–27).