My standard gauge is a t-shirt and shorts. If I can comfortably sit in the shade in shorts and no shoes, then its fine for the tortoise to be out too. I get cold easily and hate cool weather. If you are one of those people that feel hot when its 12 degrees outside, then use a thermometer instead.
Your tortoise should have a heated night box to retreat to during rain, night or cooler periods.
When my days are heating up to 35+ (We got up to 45+ here last week…), I'll let night temps drop to around 21-22. For days that are as low as 24-30, I would keep the night box closer to 30 all the time.
Thanks Tom, I guess when it's raining, he will stay in the night box until the rain stops? I worried that he will get cold if its raining.
It usually take a couple of weeks for them to learn to use their new night box, but yes, in theory, your tortoise will hopefully get out of the cold rain. Sometimes mine choose to come out in the rain. Sometimes they go back in, but sometimes they get cold and park somewhere in the cold mud. Be cautious about this. No harm in bringing them in if you think it might be cold and rainy and you won't be home for hours.