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Date and Time (datetime and zoneinfo)

Python supplies the datetime and zoneinfo modules to represent, manipulate, format, and calculate timestamps across calendars and timezones.

Core Classes in the datetime Module

  • date: Represents year, month, and day (e.g. 2026-09-14).
  • time: Represents time of day independent of date (e.g. 13:30:00).
  • datetime: Combines both date and time into a single object.
  • timedelta: Represents a duration or difference between two dates/times.
  • timezone: Represents a fixed offset from UTC.

1. Creating and Getting Current Time

Example: Current Date and UTC Time
from datetime import datetime, date, timezone

# Today's date
today = date.today()
print("Today's Date:", today)

# Current UTC datetime (Recommended standard for servers and databases)
utc_now = datetime.now(timezone.utc)
print("Current UTC:", utc_now)

2. Formatting Dates (strftime)

Use .strftime(format) to format a datetime object into a readable string:

Common Format Directives

Directive Meaning Example
%Y Year with century as a decimal number 2026
%m Month as a zero-padded decimal number 09
%B Full month name September
%d Day of the month as zero-padded decimal 14
%A Full weekday name Monday
%H Hour (24-hour clock) 00 to 23 13
%I Hour (12-hour clock) 01 to 12 01
%p AM or PM PM
%M Minute as zero-padded decimal 00 to 59 45
%S Second as zero-padded decimal 00 to 59 20
Example: Formatting Datetimes
from datetime import datetime

dt = datetime(2026, 9, 14, 15, 30, 0)
formatted = dt.strftime("%A, %B %d, %Y at %I:%M %p")
print(formatted)
Output
Monday, September 14, 2026 at 03:30 PM

3. Parsing Strings into Dates (strptime)

Use datetime.strptime(date_string, format) to parse a string into a datetime object:

Example: Parsing Strings
from datetime import datetime

date_str = "2026-10-31 18:45"
parsed_dt = datetime.strptime(date_str, "%Y-%m-%d %H:%M")

print("Parsed Year:", parsed_dt.year)
print("Parsed Month:", parsed_dt.month)
print("Parsed Day:", parsed_dt.day)
Output
Parsed Year: 2026 Parsed Month: 10 Parsed Day: 31

4. Date Arithmetic with timedelta

Calculate past or future dates by adding or subtracting timedelta:

Example: Calculating Date Differences
from datetime import datetime, timedelta

current_time = datetime(2026, 9, 14, 12, 0, 0)

# Add 7 days and 3 hours
future_time = current_time + timedelta(days=7, hours=3)
print("Future:", future_time)

# Difference between two dates
difference = future_time - current_time
print("Days Difference:", difference.days)
print("Total Seconds:", difference.total_seconds())
Output
Future: 2026-09-21 15:00:00 Days Difference: 7 Total Seconds: 615600.0

5. Working with Timezones (zoneinfo)

Python 3.9+ includes the zoneinfo module, which uses the system's IANA time zone database:

Example: Converting Across Timezones
from datetime import datetime, timezone
from zoneinfo import ZoneInfo

# Create UTC time
utc_time = datetime.now(timezone.utc)

# Convert to New York and Tokyo local times
ny_time = utc_time.astimezone(ZoneInfo("America/New_York"))
tokyo_time = utc_time.astimezone(ZoneInfo("Asia/Tokyo"))

print("New York:", ny_time.strftime("%Y-%m-%d %H:%M:%S %Z"))
print("Tokyo:   ", tokyo_time.strftime("%Y-%m-%d %H:%M:%S %Z"))