What formula can I use to identify gaps in my temperature records?

Hello, I have a Numbers file where I write the temperatures and on them I calculate a multitude of parameters; in particular, I am looking for a formula that allows me to see, on a basis of 365 days or a calendar year, how many days the temperature data are missing. Thanks to this formula I can understand if the results of a certain location can be given good or not. I was thinking of a similar thing: look at the photo.

(In the first photo look at the AV2 cell). In the second photo it is understood that the formula I am looking for, and that returns that value to me, must draw the data in the first sheet where there are all the temperatures from January 1 to December 31.

To make you understand better, if for example, on 10 days of minimum temperatures, two days of minimum temperature values are missing, then the formula must return this to me: "2/10", because there are two days of missing data out of 10; so since my base is always that of a year, that is 365, I would like the formula to return me "2/365". thank you in advance.