The internal temperature of hamburgers is an important factor in ensuring they are safe to eat and cooked to the desired level of doneness. Here are some key points from the search results:

• The USDA marks the minimum safe temperature for ground beef as 160 degrees Fahrenheit (71 degrees Celsius).
• If you like your burgers less done, aim for one of the following temperatures:
  • Medium-rare: 130° to 135° Fahrenheit (54° to 57° Celsius)
  • Medium: 140° to 145° Fahrenheit (60° to 63° Celsius)
  • Medium-well: 150° to 155° Fahrenheit (66° to 68° Celsius)
• To achieve the best temperature possible, pull your burgers at 155°F (68°C) due to carryover cooking.
• Burgers should be cooked at medium-high to high heat, meaning somewhere between 350 and 400 degrees Fahrenheit (176 to 204 degrees Celsius).
• Use a meat thermometer to check the internal temperature of the burgers. Insert the thermometer horizontally from the side to reach the thickest part of the burger and get an accurate read.
• Thinner patties will be done on the earlier side and extra-thick patties may need a bit longer, so always use your thermometer to be safe.

In summary, hamburgers should be cooked to a minimum internal temperature of 160°F (71°C) to ensure they are safe to eat. However, if you prefer your burgers less done, you can aim for a lower temperature. Use a meat thermometer to check the internal temperature and cook the burgers at medium-high to high heat.