This weekend, Europeans will be changing their clocks, as part of a twice-yearly adjustment known as "daylight saving time" in North America (which changed clocks earlier this month). The idea is that by changing our clocks, we can enjoy more hours of summer sun.
But changing the clocks is highly controversial, with many people arguing that we should stop it. And indeed, a number of countries that used to change their clocks no longer do so.
(For an interesting essay on the topic, check out https://www.joshbarro.com/p/this-week-in-the-mayonnaise-clinic-ba9.)
This week, we'll look into daylight saving time from a variety of perspectives, including where it's done, what countries do it, how long it lasts, and how many countries have observed it in each year.
Paid subscribers, both to Bamboo Weekly and to my LernerPython+data membership program (https://LernerPython.com) get all of the questions and answers, as well as downloadable data files, downloadable versions of my notebooks, one-click access to my notebooks, and invitations to monthly office hours.
Learning goals for this week include scraping Web sites, working with dates and times, grouping, and plotting with Plotly.
Data and five questions
This week's data comes from the "Time and date" web site, which has a dedicated overview about daylight saving time at https://www.timeanddate.com/time/dst/statistics.html and detailed, per-country info for 2026 at https://www.timeanddate.com/time/dst/2026.html . We'll use both of these.
Here are my five questions for this week. I'll be back tomorrow with solutions and explanations:
- From the 2026 DST info page, create a data frame for each country, in which the
startandendcolumns aredatetimevalues indicating when DST starts and ends. If the country doesn't observe DST, then you can use NaT ("not a time"). - How many countries won't change their clocks at all? Of those that do, what is the most common date for starting? As of today, how many have started it already?