How to Use dt.month in pandas to Extract Month from Dates

In pandas, you can use dt.month to extract the month as an integer from a datetime column in a DataFrame or Series. This attribute returns values from 1 (January) to 12 (December) for each date entry.

Syntax

The dt.month attribute is used on a pandas Series or DataFrame column that contains datetime values. It extracts the month part as an integer (1 to 12) from each datetime entry.

Syntax pattern:

• your_datetime_series.dt.month

Here, your_datetime_series must be of datetime type (e.g., datetime64[ns]).

python

your_datetime_series.dt.month

Example

This example shows how to create a pandas DataFrame with a datetime column and extract the month from it using dt.month.

python

import pandas as pd

data = {'date': ['2023-01-15', '2023-05-20', '2023-12-31']}
df = pd.DataFrame(data)
df['date'] = pd.to_datetime(df['date'])  # Convert to datetime

df['month'] = df['date'].dt.month
print(df)

Output

        date  month
0 2023-01-15      1
1 2023-05-20      5
2 2023-12-31     12

Common Pitfalls

Common mistakes when using dt.month include:

• Trying to use dt.month on columns that are not datetime type, which causes an error.
• Forgetting to convert strings to datetime before using dt.month.

Always ensure your column is converted using pd.to_datetime() before extracting the month.

python

import pandas as pd

data = {'date': ['2023-01-15', '2023-05-20', '2023-12-31']}
df = pd.DataFrame(data)

# Wrong: This will raise an error because 'date' is string type
# df['month'] = df['date'].dt.month

# Right: Convert to datetime first
df['date'] = pd.to_datetime(df['date'])
df['month'] = df['date'].dt.month
print(df)

Output

        date  month
0 2023-01-15      1
1 2023-05-20      5
2 2023-12-31     12

Quick Reference

Summary tips for using dt.month:

• Use only on datetime columns or Series.
• Returns integer month values from 1 to 12.
• Convert strings to datetime with pd.to_datetime() first.
• Works well for filtering or grouping data by month.

Key Takeaways

Use dt.month on datetime columns to get month numbers from 1 to 12.

Always convert string dates to datetime type with pd.to_datetime() before using dt.month.

Applying dt.month on non-datetime columns causes errors.

Extracted month values help in filtering and grouping data by month.

The dt accessor provides many other datetime parts like day, year, and weekday.