Exodus Timekeeping

My time travelers, naturally, think of time in hours and minutes. One of them even has a digital watch. But how do the Ancient Egyptians—and more specifically, the Hebrews allegedly living there—tell time in the New Kingdom, around 1300 BCE?

Torah mentions various timekeeping specifics, which mostly reflect the society when the Torah was written (many hundreds of years after the Exodus, and not in Egypt). Because my story takes the Torah as canon (meaning I use the factual truth of the stories, not just the spiritual truth), I am using timekeeping as mentioned, even if it conflicts with how the Egyptians did it in the same era.

The Calendar

I explored an Exodus Calendar in a previous post, though that was about matching up Gregorian and Hebrew dates and figuring out the Hebrew date of the first Passover.

Torah is clear that the Hebrews began to use the Hebrew calendar as they prepared to leave Egypt. Yet the Hebrew calendar as used today wasn’t really in place until the 12th century CE. In the 10th century BCE, the Hebrew calendar was fully lunar (not adjusted for drift), the months don’t have proper names, and the year began in the fall (not in the month of Nissan as stated in Exodus). Even though the Exodus would have taken place in the 14 century BCE, I am using the Torah references.

Start and End of Day

What’s not clear is when the day began and ended. In modern Western culture, we use midnight (the opposite of noon, something all cultures can easily note). The last plague took place at midnight. Egyptian culture used dawn (first light). The Hebrew calendar uses sunset/twilight.


There are also differences in how the day is divided. Modern culture around most of the world uses hours and minutes. 60 seconds make up a minute. 60 minutes make up an hour. 24 equal hours make up a full day (which includes night).

Judaism in many places, even today, uses the Relative Hour aka the halachic hour. In this system, the daylight (dawn to the appearance of 3 stars in the sky) is divided into 12 equal parts. The night is as well.

The actual length of an hour varies by day of the year and location. Even on the same day in the same place, an hour of the day and an hour of the night will rarely be the same length.

This system is not mentioned in Torah and does not seem to show up as such until the Mishnah (second century BCE, after the Torah was written).

Sundials and Shadow Clocks

Changing durations for hours, however, were part and parcel for shadow clocks, the earliest sundials. Because of the tilt of the Earth, it takes longer in summer to go from sunrise to sunset, and shorter in winter. While some sundials can correct for this, one used by Egyptian workers in the New Kingdom (c. 1500 BCE) does not.

University of Basel – Valley of the Kings, Egypt
World’s oldest Sundial, from Egypt’s Valley of the Kings (c. 1500 BC)

The Egyptian sundials are thought to be the earliest division of the day into hour-like chunks.

As early as 1500 B.C., the Egyptians had developed a more advanced sundial. A T-shaped bar placed in the ground, this instrument was calibrated to divide the interval between sunrise and sunset into 12 parts…The next-generation sundial likely formed the first representation of what we now call the hour. Although the hours within a given day were approximately equal, their lengths varied during the year, with summer hours being much longer than winter hours.

Why is a minute divided into 60 seconds, an hour into 60 minutes, yet there are only 24 hours in a day?

Ancient Israelites adopted the Babylonian system of 24 equal hours in a day, but not until Talmudic times in the Common Era. Another article attributes equal hours to Greek astronomers in the Hellenistic period of the 2nd century BCE and says the Babylonians had 60 hours, not 24.


While they certainly understood the concept of time, and had complex mathematics, they didn’t have an easy way to measure hours or minutes consistently. The idea of hours is quite old, even if they don’t match modern hours, but minutes didn’t come into being until quite late.

It was not practical for the general public to consider minutes until the first mechanical clocks that displayed minutes appeared near the end of the 16th century.

Why is a minute divided into 60 seconds, an hour into 60 minutes, yet there are only 24 hours in a day?

Timekeeping Devices

Water clocks existed in Ancient Egypt during the New Kingdom and were used to keep track of time during the night, but they would not have been standardized enough for each slave village to have one or more. And they weren’t particularly portable. Hourglasses would be more portable, if not standardized, but there is no record of them until the Middle Ages.

The Nightly Watches

Instead, the Ancient day was broken up into descriptive chunks of time. The nighttime was made up of several watches. But to learn more, go to the next post, The Morning Watch.


1 Comment

  1. The Morning Watch – Out of Egypt

    July 13, 2020 at 8:54 pm

    […] into descriptive chunks of time. The nighttime was made up of several nightly watches. For more on Exodus Timekeeping, see my previous […]

Leave a Reply

Your email address will not be published. Required fields are marked *