Setting Locales in SharePoint 2010 Enterprise can be a tricky subject as it has to be done in at least 3-4 locations to get it right otherwise your dates and calendars will invariaby be incorrect. This is sometimes due to the default installation being set up as the USA locale.
This problem presents an isssue for team sites having incorrect list dates for default list items and also web applications having incorrect dates. This would also be evident when My Sites is on a seperate web application than other sites.
To correct this perform the following (ensure you have a farm administrator account and also a Site Collection Administration account for My sites).
1.Log on to the Central Administration Account and navigate to Application Management > Manage Web Applications
2. You will now be brought to the Web Applications screen. Click once on the name of the web application that is to be changed and then click on the "General Settings" tab.
3. The web application general settings page will apper. On the Choose the Default Time zone, click on the select time zone drop down button and select a time zone relevant to your local i.e. UK. Click on the OK button once complete.
4. Repeat these steps for any other web application that you may have.
5. Next thing to do is to change the Regional settings within Central Administration. (There doesn't appear to be a button / link for this on Central Administration so the best thing to do is to enter the URL directly which is "http://your-centraladmin-root-url/_layouts/regionalsetng.aspx (replacing "your-centraladmin-root-url" with that of your Central Administration site.
6. On the Regional settings screen, change the locale to your locale i.e. UK (or any other relevevant locale and change the Time Zone as well). Here, we are using Greenwich Mean Time: Dublin, Edinburgh, Lisbon, London for the UK. Once completed, click on the OK button at the bottom of the screen and this completes the changes on Central Administration.
7. Next, log into your SharePoint and navigate to main site collection (you need to be a site collection administrator). On the ribbon, click on Site Actions > Site Settings.
Navigate to Site Administration > Regional Settings
8. If necessary, change the locale and time zone details as well for the site collection