It's always the right time to calibrate your oven, but it's essential before a holiday. Why? Well, you don't want that turkey to be underdone or those cookies to be burned to a crisp. Plus, oven temperature accuracy can drift over time, so it's best to check it periodically and especially before you're going to be putting your oven through a workout.
If you feel like you're constantly having to adjust cooking times listed in recipes for your finicky oven, you need to calibrate it. Luckily, it's super simple!
Checking an oven's calibration involves ensuring that the average temperature is what you've set it at, not that it's constantly at that temperate. It may fluctuate 20-30 degrees in either direction as it cycles, so don't be too alarmed as you take your readings.
Set a rack in the middle of the oven
Hang an oven thermometer in the center that rack and preheat the oven to 350˚F/177˚C
At the end of the preheating cycle, take a temperature reading to see if your oven has actually reaching the set temperature
Continue taking readings every 20 minutes for the 90-120 minutes
Average the readings
Hopefully, your average will be 350! If not, you'll be able to see by how many degrees your temperature is off by. At that point, follow the directions for your specific make and model of oven to offset the temperature setting (most will allow you to alter temperature settings by +/-25˚).
Pro tip: Try and check the temperature without opening the oven door. That drops the temperature and will making your readings less accurate. If you are unable to see through your oven door, you might want to invest in a digital thermometer with an air probe and a grate clip (the ThermoWorks ChefAlarm is great for this!).