When a new season arrives the fruit should be sized, don´t you think? With fruit, jam jars and enthusiasm.
And to make a jam or a marmalade you need this three. Without fruit, nothing happens. If you are reluctantly, all goes wrong. Without jars, it won´t preserve well.
This jam can be done at any time of year, we always have mandarins, at least here, in Argentina. But also it can be done with oranges.