Automatic update when the app or the city's tab is opened

[opk12]

My usage pattern is:

• Tap to open the app.
• Possibly switch tab.
• Tap Update.

I do not need to view old data. Some day I may not check the hour and wrongly think the information is up-to-date. It would be handy if opening the app, or switching the tab, triggered an automatic update, without showing the old data (or graying it out, etc).

These are not alternatives for my case:

• Updating every few minutes would drain the battery, use the data connection, not match the exact time that I use the app.
• The widget cannot be on my default homescreen panel (because it distracts me and takes screen space). Additional interaction would be necessary to reach another homescreen panel and return back, but I'd like to minimize interaction.