Creating outlook calendar event with href changes time by 1 hour

Question

I am struggling with these 2 links. They both allow events to created in Outlook via a href link.

This first link works fine. The date in UTC format, 2023-03-24, starting at 09:00 and ending at 10:30 on the same day

https://outlook.office.com/owa/?path=/calendar/action/compose&startdt=2023-03-24T09%3A00%3A00%3A000Z&enddt=2023-03-24T10%3A30%3A00%3A000Z&subject=Placeholder&rru=addevent

When I follow this link above, it creates an event in my calendar at the expected time and date

This link is the same other than starts 2023-03-31, starting at 09:00 and ending at 10:30 on the same day

https://outlook.office.com/owa/?path=/calendar/action/compose&startdt=2023-03-31T09%3A00%3A00%3A000Z&enddt=2023-03-31T10%3A30%3A00%3A000Z&subject=Placeholder&rru=addevent

When I click this link, it creates a link 1 hour late, from 10am until 11:30 on the 31st.

I don't understand the behaviour or what I need to change

Answer 1

From the format of those dates, eg :

2023-03-31T09:00:00:000Z

Indicates it's in UTC format which doesn't change when the clocks do. But 2023-03-24 and 2023-03-31 are either side of when the clocks changed. So the link is generating the same time for both appointments and not compensating for the clocks changing, but Outlook IS making that adjustment.

Answer 2

Are you in a country that uses Daylight Saving Time (DST) ? If so, it's likely to be the cause of the 1 hour difference you observed on 2023-03-31.

If you are intended to create a meeting starts 2023-03-31, starting at 09:00 and ending at 10:30, manually adjust the time to one hour ahead in the link you used:

https://outlook.office.com/owa/?path=/calendar/action/compose&startdt=2023-03-31T08%3A00%3A00%3A000Z&enddt=2023-03-31T09%3A30%3A00%3A000Z&subject=Placeholder&rru=addevent