How to localize date fields?

Maybe it is against the rules to answer to my own question, but I found the solution:

- The actual report shows properly either English or Finnish depending on the personal server settings: General -- > Language -- > <your locale>

(see https://app.powerbi.com/groups/me/settings/general )

- Desktop perhaps sometimes uses the locale from Windows and sometimes the locale I have defined to Desktop, so if this would trouble me, I could try to change my Windows locale.

Localization

Users

• Change your personal server settings General -- > Language -- > <your locale>

Example link: https://app.powerbi.com/groups/me/settings/general?redirectedFromSignup=1

Development

• Locale settings inside Desktop are determined from more than one place:
  1. Windows settings
  2. Default regional settings
  3. Locale settings of the current file
  4. NOTE: Desktop language is irrelevant from 2019-12 onwards. You can overwrite all of the language settings.
• To change the last two, open your report with Desktop
• From desktop version 2019-12 onwards, open File -- > Options and Settings -- > Options -- > Global -- > Regional Settings and here you have two options.

For English speakers I recommend that you change the model language only.

Non-English speakers may use the same or if they wish to see inconsistent translations then they could use the settings on below:

Example case “Latest UTC date” looks good heading in English, but bad in Finnish “Viimeisin UTC date”

Note: This setting only affects new reports, not existing reports!

• “Global” settings don’t change everything, you may also need to alter file based settings.

Select File -- > Options and Settings -- > Options -- > Current file -- > Regional Settings -- > Locale for import -- > <your locale>

• Refresh your data!
• Note that this localization changes currency as well. So if the actual currency is in US$, these settings will show it as Euros. As Power BI doesn’t support custom types the way SSRS does, you may need to change the column as text format to prevent any changes on currency.
• That should be enough, but if you have a special case, then you may need to convert the locale with Power Query. Example case:

#"Content" = Table.TransformColumnTypes(#"Localized content", {{"Local timestamp without offset", type datetime}}, "fi-FI"),

I wrote this as a blog article to here:
https://community.powerbi.com/t5/Community-Blog/Localization-in-Power-BI/ba-p/952439