|Get yourself a thermometer for down there.|
You can get inexpensive devices that monitor the relative humidity in the air. Use one of those in the basement. If it shows, say, 70% or less, you're fine.
This guy in a recent Topic has his computer in a cool room that has shown as low was 11C (51.8 F) in the current bios readings and it seems to be working fine.
See Response 58 and 59
He quoted the temp outside too. That's not relevant.
The temp where I am was -38 C outside on one day a short while before Xmas, but where my computer is in the heated and insulated basement never gets below about 15 C or so (59 F) in the winter, and that's only when we're sleeping - we keep the furnace thermostat upstairs set to no less than 20 C (68 F) at night - it might get a bit cooler there in the spring and fall when the furnace doesn't come on as often.