I’ve been working on my Platinum Trophy for Persona 4 Golden for about 25 years at this point (it’s been a very leisurely journey), and in my second playthrough I went and maxed out all the social links. There are a lot of guides on availability, but I couldn’t find a good chart, so I made one.
Some of the availability gets wonky around test times, on Sundays, and in the Winter period, but this is what helped me plan my wistful high school days.
The only links available on rainy days are:
These social links take up your evenings (weather doesn’t matter):
Hanging out with friends really helps move things along but you should always have things planned out for the week and Personas of the appropriate Arcana ready to level up as fast as possible.
And here’s a Google doc link.