Issue
With one of my flows, I was using an Azure function to generate a filename for my Azure logic app. This name was generated based on the date…
What did I see happening…
As I the script ran just after midnight, I saw that I was getting the day before instead of the actual date.
The Cause
By default, the Azure App Service / Webapp / Functions are running in UTC/GMT. Though I configured my logic apps to use the timezone “CET” (UTC/GMT+1)
When checking with “kudu”, I saw I had a mismatch on my hand…
The Fix
Apparently there is an easy fix! So let’s try that one… Via the registry I checked for the official windows name for my time zone, being the “Std”-value (“W.Europe Standard Time”).
I went to the “Function app settings”
And selected “Application settings” on that page
Here I added an app setting called “WEBSITE_TIME_ZONE”, where I entered my time zone (std-value).
Press save and … wait for it.
Afterwards, all was okay!
Karim Vaes 
The list of timezones seems to be online here: https://msdn.microsoft.com/en-us/library/ms912391(v=winembedded.11).aspx
Hi. I follow your instructions and work fine. Thanks!
But i have a question… because, although now if a function do Date.Now inside it, will return the correct date and time, but on the registry console still appears a wrong date.
How to Handle UK daylight saving in time-based azure function
i want to know this too.
Check Vladimir’s comment… 😉