How to plot a time series in Python?

To plot a time series in Python using matplotlib, we can take the following steps −

• Create x and y points, using numpy.

• Plot the created x and y points using the plot() method.

• To display the figure, use the show() method.

Basic Time Series Plot

Here's a simple example that creates hourly data points for a full day ?

import matplotlib.pyplot as plt
import datetime
import numpy as np

plt.rcParams["figure.figsize"] = [7.50, 3.50]
plt.rcParams["figure.autolayout"] = True

# Create datetime points for 24 hours
x = np.array([datetime.datetime(2021, 1, 1, i, 0) for i in range(24)])
y = np.random.randint(100, size=x.shape)

plt.plot(x, y)
plt.xlabel('Time')
plt.ylabel('Value')
plt.title('Time Series Plot')
plt.show()

Using Pandas for Time Series

Pandas provides better support for time series data with built-in plotting capabilities ?

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt

# Create date range
dates = pd.date_range('2021-01-01', periods=30, freq='D')
values = np.random.randn(30).cumsum()

# Create DataFrame
df = pd.DataFrame({'value': values}, index=dates)

# Plot using pandas
df.plot(figsize=(10, 4))
plt.title('30-Day Time Series')
plt.ylabel('Cumulative Value')
plt.show()

Adding Formatting and Labels

For better visualization, add proper formatting, labels, and rotation for dates ?

import matplotlib.pyplot as plt
import pandas as pd
import numpy as np

# Generate sample data
dates = pd.date_range('2021-01-01', periods=12, freq='M')
sales = np.random.randint(1000, 5000, size=12)

plt.figure(figsize=(10, 6))
plt.plot(dates, sales, marker='o', linestyle='-', linewidth=2)
plt.title('Monthly Sales Data', fontsize=16)
plt.xlabel('Date', fontsize=12)
plt.ylabel('Sales ($)', fontsize=12)
plt.xticks(rotation=45)
plt.grid(True, alpha=0.3)
plt.tight_layout()
plt.show()

Key Points

• Use datetime objects for the x-axis when dealing with time data

• Pandas date_range() simplifies creating time sequences

• Always add proper labels and titles for clarity

• Use plt.xticks(rotation=45) to rotate date labels for better readability

Conclusion

Python's matplotlib and pandas make time series plotting straightforward. Use datetime objects for proper time axis formatting, and pandas for more complex time series operations with built-in plotting methods.