Hot. Blazing hot! But not as hot as you think.
A butane torch burns at very close to 5,000 °F (4,995 °F, to be exact). While that's way hotter than your oven, it's not quite hot enough for a lot of jewelry and metal work, which is why crafty and construction-type folks tend to prefer a 6,000+ degree acetylene torch, or even a 5,000+ degree propane torch.
Need more information? Newspaper archives are one of the best online research tools.