Pass Values

I have a website that runs weather forecasts using wordpress and JSON feeds from several different sources. All that information is setup. I am looking for a way to have 4 different custom values that I could fill in when creating a new page. These custom values would then use a tag of some sort like {customvalue1} and show in the page wherever I need it to show without using any shortcode at all. This tag will need to work with my existing template system and page setup. I DON"T NEED A CUSTOM PAGE TEMPLATE. I only need the function described above using custom fields that will show on every new page that is created with the site.