This is a niche widget retail site created in 1999, fully responsive and updated/checked about once a month. It ranks extremely well, many first places, for all its keywords and subjects and dominates the localised SERPs for its widgets, 89.3% of its traffic is from the UK.
I have loads of data for this site and it's been very consistent over the past 20 years however this year has seen an unusual pattern with traffic loss every month as follows:
February -5%
March -3%
April -5%
May -5%
June -10%
July -9%
August -16%
So, overall from January to August a 43% reduction in traffic meanwhile a -26% in uniques.
The start to September was absolutely diabolical yet I could find absolutely no reason for the continued loss in traffic however since the 5th September the site seems to have found a new life and IF traffic continues at this level it will be back to March numbers with an increase of PVs 62% and uniques back to "normal".
I've never had any site that's done anything like this before, has anyone else experienced similar?
FWIW the actual business has been doing fine.