1a) giorno
1b) giornata
What's the difference?
'Giorno' is a time lapse of 24 hours, and approximately 85000 secinds, which MUST be contiguos, etc.
'giornata' is much more fun! as it is 'giorno' restricted to what happens during the time we are (usually) awake, AND -- here is the fun -- including the relevant things that regard us.
Therefore 'giornata' is 'day' plus a personal history, that for sane things, like weather conditions are shared among many people.
That's also why, we enjoy more in saying 'Buona giornata' instead of the usual 'Buon giorno'.
Similar considerations regarding:
2a) sera, 2b) serata; 3a) Notte, 3b) Nottata
But we don't say 'buona nottata', as we assume that 'night' has not a story in it, at least
not stories to be told, but, if you leave a co-worker knowing he or she must work and drink coffee to stay awake for those long hours,
'buona nottata' is fine.
One correction:
Durante l'autunno scorso e per tutto l'inverno le giornate erano quasi tutte buie.
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Oggi é stato bello, proprio il primo giorno di primavera. Durante l'autunno scroso e tutto inverno dei giorni erano quasi tutti bui. Parecchi giorni a turno senza nessun luce di sole sono stati insostenibili. Persino quando sto sempre lavorando da casa. E oggi sono quasi corso in un parco vicino