But, since you posted it here I couldn't resist adding/tweaking it a bit

Among the useless things I did was renaming getC and GetF, mostly
because getC rings like an age old io function to me...

Code:
import java.util.*;
import java.text.*;
/**
 * A sortable, formatted and printable temperature class
 *
 */
public class Temperature implements Comparator   { //Class name
  /**
   * format for printing temperature values
   */
  static DecimalFormat df=new DecimalFormat("0.0");
  double temp; //Variable

  char scale; //Varible

  public Temperature() { //Default Constructor
    temp = 0;
    scale = 'C';
  }

  public Temperature(char tempScale) { //Scale Constructor
    temp = 0;
    scale = tempScale;
  }

  public Temperature(double tempValue) { //Temp Constructor
    temp = tempValue;
    scale = 'C';
  }

  public Temperature(double tempValue, char tempScale) { //Constructor
    temp = tempValue;
    scale = tempScale;
  }

  public double getCelsius() { //Used to get degrees C
    double value;
    if (scale == 'C') {
      return temp;
    }
    else {
      return ( (double) (Math.round( (5 * (temp - 32.0) / 9.0) * 10.0)) / 10);
    }
  }

  public double getFarenheit() { //Used to get degrees F
    if (scale == 'F') {
      return temp;
    }
    else {
      return (Math.round( (9 * (temp / 5) + 32) * 10) / 10);
    }
  }

  public void setTemp(double newTemp) { //set temp
    temp = newTemp;
  }

  public void setScale(char newScale) { //set scale
    scale = newScale;
  }

  public void setTempScale(double newTemp, char newScale) { //set both
    temp = newTemp;
    scale = newScale;
  }
  /**
   * return a formatted temperature string
   * @return
   */
  public String toString () {
    return df.format(temp)+" "+scale;
  }
  /**
   * the equals method should be implemented as an override of the
   * Object class' equals method, parameter should be an Object.
   * Note: the two next metods define the Comparator interface
   * Among othjer things this enables sorting.
   * @param obj
   * @return
   */
  public boolean equals(Object obj) { //compares for equality
    if (!(obj instanceof Temperature)) {
      return false;
    }
    Temperature aTemp=(Temperature)obj;
    return (getCelsius() == aTemp.getCelsius());
  }
  /**
   * Method used by  Collections.sort
   * @param o1
   * @param o2
   * @return
   */
  public int compare(Object o1, Object o2) {
    Temperature t1=(Temperature)o1;
    Temperature t2=(Temperature)o2;
    // switch t1 & t2 here to get descending sort
    return (int)(t1.getCelsius()*10.0d-t2.getCelsius()*10.0d);
  }
  // This is comparing statements to see if the first is greater than the second
  public boolean greaterThan(Temperature obj) {
    return (getCelsius() > obj.getCelsius());
  }

  // This is comparing  statements to see if the first is less than the second
  public boolean lessThan(Temperature obj) {
    return (getCelsius() < obj.getCelsius());
  }

  // Returns temp value
  public double getTemperatureTemp() {
    return temp;
  }

  // Returns scale character
  public char getTemperatureScale() {
    return scale;
  }

  public static void main(String[] args) {
    Temperature t = new Temperature(100.5, 'C');
    System.out.println("\n\nt:"+t);
    // stuff an arrayList with temperatures and sort them on actual heat value
    ArrayList tList=new ArrayList();
    tList.add(t);
    tList.add(new Temperature(140.5,'F'));
    tList.add(new Temperature(60,'C'));
    tList.add(new Temperature(90,'F'));
    tList.add(new Temperature(70.3,'C'));
    tList.add(new Temperature(.7,'C'));
    // the 'new Temperature()' parameter here is just a dummy for using the
    // Temperature class' Comparator
    Collections.sort(tList,new Temperature());
    System.out.println("Sorted temperatures");
    for (int i=0; i<tList.size(); i++) {
      System.out.println(tList.get(i));
    }
  }
}