We don't currently have any specific settings in place for seasonal foods, as we have users in a variety of different regions with varying seasonal offerings. We would suggest customizing this using the food exclusions and recurring foods features.
Food Exclusions
The food exclusions can be used to exclude ingredients that are out of season in your area. These can be easily added and removed, so you can go in to select/de-select these items and adjust this seasonally. See more about setting up exclusions here: How do I exclude gluten, dairy, or other foods I don't like/want to avoid?
Recurring Foods/Collections
Recurring foods can be set in the meal settings for each meal, which will let the generator know to incorporate these options more often.
You could use this to set up some of your favorite in-season options and adjust this seasonally as well. You might even consider creating seasonal collections of foods, which would allow you to quickly set a full collection of recipes to recur, which you can easily remove and add back next season. You can see more about these options in the articles below.
Using Recurring Foods to incorporate more of your preferred foods