Unfortunately, we are not able to tell you the exact sales dates.
However, we usually have a sales plan that extends over several months, with the discounts then increasing the further we get in the process.
When the sale ends, the sale category on the website will disappear. You will probably still be able to access via an old link, but you won't be able to purchase the item at sale price anymore.
If you want to know more, please sign up for Newsletter or contact the customer care team.