Python strftime directive %j
Day of the year, zero-padded (001–366).
Example (from datetime(2026, 6, 18, 13, 45, 30))
169
In Python
from datetime import datetime
dt = datetime(2026, 6, 18, 13, 45, 30)
dt.strftime("%j")
# => "169"Parsing with strptime
Parses a 1–3 digit day of year. See strptime.dev for the parsing side.