How to Extract Hour from Datetime in pandas Easily

To extract the hour from a datetime column in pandas, use the .dt.hour accessor on a datetime Series. This returns the hour as an integer from 0 to 23 for each datetime value.

Syntax

Use the .dt.hour attribute on a pandas Series with datetime values to get the hour part.

• Series.dt: Accessor for datetime properties.
• hour: Extracts the hour (0-23) from each datetime.

python

df['hour'] = df['datetime_column'].dt.hour

Example

This example shows how to create a pandas DataFrame with datetime values and extract the hour from the datetime column.

python

import pandas as pd

data = {'datetime_column': ['2024-06-01 08:45:00', '2024-06-01 15:30:00', '2024-06-01 23:59:59']}
df = pd.DataFrame(data)
df['datetime_column'] = pd.to_datetime(df['datetime_column'])
df['hour'] = df['datetime_column'].dt.hour
print(df)

Output

       datetime_column  hour
0 2024-06-01 08:45:00     8
1 2024-06-01 15:30:00    15
2 2024-06-01 23:59:59    23

Common Pitfalls

Common mistakes include trying to extract the hour from a column that is not in datetime format, which causes errors or incorrect results. Always convert the column to datetime using pd.to_datetime() before extracting the hour.

Another mistake is using string methods instead of datetime accessors, which is less efficient and error-prone.

python

import pandas as pd

data = {'datetime_column': ['2024-06-01 08:45:00', '2024-06-01 15:30:00']}
df = pd.DataFrame(data)

# Wrong: trying to extract hour without datetime conversion
# This will raise an error
# df['hour'] = df['datetime_column'].dt.hour

# Right: convert to datetime first
df['datetime_column'] = pd.to_datetime(df['datetime_column'])
df['hour'] = df['datetime_column'].dt.hour
print(df)

Output

       datetime_column  hour
0 2024-06-01 08:45:00     8
1 2024-06-01 15:30:00    15

Quick Reference

Operation	Code Example	Description
Convert to datetime	df['col'] = pd.to_datetime(df['col'])	Ensure column is datetime type
Extract hour	df['hour'] = df['col'].dt.hour	Get hour (0-23) from datetime
Check dtype	df['col'].dtype	Verify column type is datetime64[ns]

Key Takeaways

Always convert your column to datetime type before extracting the hour using pd.to_datetime().

Use the .dt.hour accessor on a datetime Series to get the hour as an integer from 0 to 23.

Avoid using string methods to extract time parts; datetime accessors are more reliable and faster.

Check your column's data type with .dtype to ensure it is datetime before extraction.

Extracting the hour is useful for time-based analysis like grouping or filtering by hour.