Converting datetime.date to UTC timestamp in Python

python

datetime

timestamp

utc

byNikita Barsukov·Jan 6, 2025

Convert a datetime.date to a UTC timestamp in Python by uniting it with midnight time, adjusting a UTC timezone, and transforming to timestamp:

from datetime import datetime, timezone

# Substitute 'your_date' with your datetime.date object
utc_timestamp = datetime.combine(your_date, datetime.min.time(), tzinfo=timezone.utc).timestamp()

Key steps: Use datetime.combine() with datetime.min.time() for midnight. Apply .replace(tzinfo=timezone.utc) for UTC timezone, and .timestamp() for POSIX timestamp.

Understanding the power of `datetime` and `calendar`

Hurdling the local timezone confusion

Obtain a clear cut UTC timestamp bypassing local timezone worries by employing calendar.timegm():

import calendar
from datetime import datetime

# For an naive datetime.date object
naive_date = datetime(2023, 4, 1).date()
# Local timezone, who? We're going universal here.
utc_timestamp = calendar.timegm(naive_date.timetuple())

It's quite clear: UTC is the real deal, and calendar.timegm() gets you there.

Managing the floating-point precision dance

To keep precision intact when it really matters (think logging events to a nanosecond), Python's timestamp comes as a floating-point:

from datetime import datetime, timezone
from decimal import Decimal

date = datetime(2023, 4, 1, tzinfo=timezone.utc)
# So precise, it's decimal-point crazy!
timestamp = Decimal(date.timestamp())

Top Tip: A Decimal embrace ensures your timestamps don't lose precision.

Python 3.3+: embracing simplicity with elegance

Python 3.3 and later versions, add the datetime.timestamp() method which eases the path from a timezone aware datetime object to a timestamp:

from datetime import datetime, timezone

# Marvel at the aware_datetime in all its resplendent awesomeness
aware_datetime = datetime(2023, 4, 1, 12, 34, 56, tzinfo=timezone.utc)
# The output POSIX timestamp is easier on your eyes, and your code
posix_timestamp = aware_datetime.timestamp()

Fact: datetime.timestamp() sheds the conversion sweat since Python 3.3.

Handling historical dates and DST

Working with past dates or foreseeing DST and leap second corrections can be tricky. With the pytz module, this gets simpler:

from datetime import datetime, timezone
import pytz

# Aware of the timezone, we're in historical territory here
aware_datetime = datetime(2023, 4, 1, 12, tzinfo=pytz.timezone('Europe/London'))
# A POSIX timestamp now, history won't trip you up again
posix_timestamp = aware_datetime.timestamp()

Remember: Use pytz to factor in historical DST switches and leap seconds.

Surviving and thriving with Python 2 legacy code

In Python 2 lands, UTC timestamp conversion demands special care:

Sidestepping the time.mktime booby trap

time.mktime() can erroneously consider local timezone. Save your code from tumbling by opting for calendar.timegm() in Python 2:

import calendar
from datetime import datetime

naive_date = datetime(2023, 4, 1)
# Do you sense a UTC pattern here? Good, because that's how it should be!
utc_timestamp = calendar.timegm(naive_date.utctimetuple())

Wisdom for the Ages: Dodge UTC errors with calendar.timegm(). Safety first for Python 2!

Harnessing the power of timedelta's total seconds

Python 2 requires total_seconds() from the timedelta class for calculating time differences:

from datetime import datetime, timedelta

# Concentrate, timedelta is in command here.
time_difference = datetime(2023, 4, 1) - datetime(1970, 1, 1)
# Converts to seconds, as easy as pie (or maybe not!)
posix_timestamp = int(time_difference.total_seconds())