What is considered too low a range for basal cell temperature? Is it always a sign of hypothyroidism?

I’ve been doing bbt tracking, and I’ve noticed that my highest basal cell temperature in the morning was 36.8F. It’s most often between 36.1-36.5.
I believe I’ve had a thyroid test, and it was normal. I first realised my body temperature might too low when I was using a fertility chart and had to change the range since my waking temperature has never even reached 37 degrees C. I sleep pretty normally, and usually wake up naturally around the same time every day.
The thing is, I don’t tend to feel cold, and although I weigh more than I did when I was younger and can’t seem to lose it, I’m still pretty slim. I do have some symptoms that appear to be consistent with hypothyroidism, but some are not. For example, I don’t have any throat problems and I rarely ever feel cold even with a low body temperature.
Is it within a normal range, or are can it be a symptom of something besides thyroid disorders?