This may have been posted in the past but I just want to share my experience.

I went to do my spouse visa today and as required I provided a statement showing the amount of 400000b had been in my account for at least 2 months. I deposited the money on 8 January 2021 and today being 9 March I felt it adequate.

Not so according to immigration. Apparently due to February only having 28 days they want me to extend my application date to 10 March 2021. This now requires me to go back to the bank and get an updated letter and statement.

Anybody including the month of February as one of their two months should bear this in mind and add a couple of extra days to cover the shortfall in February.