I know my morning and daily temps tend to be pretty normal, say morning temp of 97.7 or above pre-ovulation and 98.4 or above post ovulation, rising throughout the day with an general average of 98.2-98.6. Depends on who you ask but my TSH tends to be on the lower end of normal: .5, .8, always less than 1. And my free T3 also is lower than optimal/normal from a functional perspective but within the lab ranges.
In my opinion this is not classic hypothroidism but low T3 syndrome/ Euthyroid sick syndrome. So maybe that is why I have normal temperatures. Or maybe as you are questioning, the correlation is not very accurate.
I don't feel like my thyroid works well from a symptomatic perspective. I have cold hands and feet, fear being cold, weak hair and nails, sparse outer eyebrows, exhaustion. Two classic hypothyroid symptoms I do not have are dry skin and weight gain. I have very oily skin and cannot gain weight.