I suppose this could apply to the Millionaire Centre too. Is there a set date when they change to the new season? I've had a look in the news, the holiday calendar and the shops themselves but there's no indication of when they'll move on to the next season. I'm in no hurry as there are still things I'm gathering from both but I do wonder how long I have left to do so. Does anyone have a rough idea of the date they'll move on to summer?
The first day of summer in the US, June 21st or so
From what I've seen it's always the first day of the season, so the solstice or equinox, depending on which season it is. :) The summer solstice this year is the 20th of June

We'll have a news post soon warning people about the switch over! We generally do it about a week beforehand :)
To add to what everyone else said, there's a forum topic for deadlines and retirement dates including when the quest shop and millionaire center change seasons. It also tells you when certain items might retire, and so on, so it's really useful. You can find this topic here: Deadlines: Retirement Reminders 2017
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