What is the purpose of including sea level pressure and temperature in a METAR? In a METAR such as this one:


  KGOK 161553Z AUTO 18011KT 4SM BR OVC007 07/05 A3011 RMK AO2 SLP201
  T00670050


Translated to:


  Jan 16, 1553Z, Automated. Mist, Wind from 180° at 11 knots, 4 statute
  miles visibility, Ceiling is Overcast at 700 feet, Temperature 7°C,
  Dewpoint 5°C, Altimeter is 30.11. Remarks: automated station with
  precipitation discriminator sea level pressure 1020.1 hectopascals
  hourly temp 6.7°C dewpoint 5.0°C


Why would I want/need to know, or what would I do with, this information in the remarks section:


  sea level pressure 1020.1 hectopascals hourly temp 6.7°C dewpoint
  5.0°C
The sea level pressure allows pilots to calibrate their altimeters to make sure they are accurate. KGOK is 1069 feet elevation, if a pilot were to set their altimeter to 1020hpa (or 30.11 inches of mercury as used in the US, that's the A3011 in the METAR) then their altimeter would read 1069ft at ground level.