Visualization in Time Series using Heatmaps in Python

From the above heatmap the month June to August has a high temperature compared to other months due to summer and the low temperature in the month of December as it is the winter season. By using the heatmap you could easily visualize the extreme low and high temperature. In the FEB period, you notice the white block because FEB has only 28 days.

Applying calplot separates each month of the year and the weekdays and provides a clean visual. we can customize the visuals as you need by adding the custom color or style to the heatmap.

timeseries data average



Here you could easily relate to the temperature with the colormap gradient added line edge is not enabled.

In the above heatmap, we included a title and made the year text color black.

heatmap code

we can also display the values inside the block and further resized the image using fig size for better visual. Here the missing values are filled with ‘-‘. However, we do not have any missing data in this dataset


Visualizing the missing values in the heatmap

missing values in the heatmap

The white block above indicates the missing value. when displaying the corresponding values in the square each missing value is substituted with ‘-‘ as we discussed before.

In calplot, if the data contains the missing value it is filled by default and replace some value with zero if it can not fill the missing value. If drop zero=False is not set then it is filled with ‘-’.

drop zero heatmap
drop zero heatmap output

we can make the line edge separating the month thicker using linewidth.

time series heatmap linewidth
time series heatmap linewidth


Custom colormap in calplot

time series Custom colormap in calplot
time series Custom colormap heatmap in calplot

To make the custom color scale make the list of hex colors and assign it to calplot. By giving the series of hex values it arranges itself to the gradient color. To reverse the gradient, rearrange the list of hex values.


When to use a calendar map?

‌‌A calendar heatmap is useful to analyze the daily values or day of the week. If we want to view daily data for the whole year, then Calendar Heat maps are helpful.

I hope you had an enjoyable time reading about my work and my insights! Any suggestions and feedback are always welcome.

About Author

I’m Kavitha a software developer and ML enthusiast fascinated by computer science and A.I.

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