I think there must have been a slight frost again last night. Today about midday heavy rumbling sound which may have been either thunder or gunfire, & soon afterwards heavy sleety rain. More showers in the afternoon. Ground is very soggy again. Could not do much out of doors owing to the rain. Dug a little patch for the shallots.
6 eggs.
Orwell Diaries 1938-1942 
“Today about midday heavy rumbling sound which may have been either thunder or gunfire, & soon afterwards heavy sleety rain.”
Are external events forcing their way in despite all he does to keep them out? Three years ago would autumn thunder have sounded like guns?
Could the bombing have started?
According to a web diary of dates in history in the UK, the only event of note on this day in 1939 was the birth of John Cleese
“… the only event of note on this day in 1939 was the birth of John Cleese”
… which would explain the rumbling sound.
Neither can I find anything in the historical records about George’s little patch for shallots. How fickle our historians are!