Press to select the Weather icon from your iPhone SpringBoard.
If this is the first time you are setting up your Weather application then it will default to Cupertino. Press the small i button at the bottom right of the screen.
You will now be presented with a list of the cities for which you can check weather.
To delete a city (ie Cupertino) press the red "Do Not Enter" button at the left side of the city name. A Delete button will then appear. Press it to remove the city from your list.
To add a city press the + button at the top left hand corner of the screen.
The Add Location window will appear. Type in the name of your city then press the Search button.
Now a list of possible results will appear. Press to select the correct location.
Notice the city now appears in your list of Weather Locations. You can continue to add more cities if you like.
You can drag the handles at the right of each location to order the cities in your list. At the bottom of your weather list you can choose between Celsius and Fahrenheit using the two large buttons. Then press the Done button at the top right to finish your changes.
You will now be taken to the weather conditions for your chosen city! You can swipe to move between cities on your list.