Thanks, it's working now. I can only conclude that the internet connection I had was dropping out. I wrongly thought that the fact that the map and location did appear meant that I had an internet connection, but I just manually turned mine off as a test: the location and map appeared but no weather. Thanks for getting back to me.
By the way, Timo, I love your app. I have searched for many years for a clear and easy-to-use diary app. I show it to people all the time, as well as the app on my phone which I use throughout the day to load usually one representative photo. This might be of the sunrise, sunset, a finished project, a place I've been, a person I met or spoke to... the delightful thing for me is to see the calendar mode covered with photos. I started using Diarium in November, so I can hardly wait to use the feature that shows what I wrote on this day in past years.