Water boils at a lower temperature at higher altitudes. Most cities and towns in Utah are high altitude. For the best results you should calibrate and adjust your thermometer for Utah's high altitudes. To calibrate your thermometer, bring a pan of water to a boil. Take the reading on the thermometer. Subtract the reading from 212. Example: Your thermometer reads 205 degrees subtract 205 from 212 and you get 7. Subtract the difference from your recipe. Example you recipe says to cook the candy to 280, but you subtract 7 from 280 and cook the candy to 273 degrees.