When I was younger satsumas and nuts were always put in stockings and they used to only be available at that time of the year or more accurately the nice ones but now you can get good quality all year.
Though I do think that walnuts in particular were better then. Now in England they are often 1 - 2 year old California ones but I did manage to get some wet English ones the other day - shame because they are wet they will not keep for Christmas but that gives a good excuse to eat them now. In fact I am eating one as I post.
To me nuts, raisins and satsumas are all part of Christmas along with chocolate money and chocolate on the tree.
Of course going back to my grandmother and great grandmother a lot of children all they got for Christmas was some fruit and if lucky nuts in a stocking.
When I was growing up, our family didn't have a whole lot of money, so Mama had to make the food budget stretch. We didn't have a lot of fresh fruit around during the year. Back in the 50's and early 60's it wasn't available like it is now, as you know. But at Christmas, Mama went to the wholesale produce merchant, who was a friend of the family, and always got a big box of apples and oranges, and a whole bunch of bananas. But she always got a little box of satsumas, too, and they were SO good.
She would keep all the fruit outside in my Daddy's workshop. I grew up in MS, so we didn't have to worry too much about them freezing; they just stayed nice and cool, until they went into our stockings, of course! ;o)
I can't smell an orange today without of thinking of Christmas.