My basals fluctuate from 11 upwards, used to be 18 at one time... But at that time of high basals I wasnt physically working as I do now.
I also notice that unwittingly my bolus's do actually go up and down in line according to seasons.... Solely because in winter my veg is .. Say tonight.. Swede, carrots, parsnips, mangetout, cabbage with chicken.. Alot of the veg high in carbs... Especially when compared to carbs in lettuce and cucumber! So although I don't really think that my food intake goes up in winter.. The carbs certainly do.. And without realising it...so I just accept that my basals will change...it is pretty much inevitable as summer I am out from 7am - 10 pm loving the sun.. ( not last year!).. And winter I am indoors doing far less.
I'm just aware that seasons affect me and make my levels change dramatically, quite quickly. Then different drugs as well... It git a huge amount to contend with.