Browser support standards

This policy applies to web browsers that are being used on desktop versions of Windows, Mac OS and Linux/Unix.

We have developed a separate mobile site  for use by mobiles; a separate policy is being developed for this.

Web browser support

The Met Office public web site has been developed to comply with the World Wide Web Consortium (W3C) AA Accessibility standards.

We have tested our site using the browsers given in the list. The various browsers are allocated a 'Level of Support' as described below.

'Levels of support' definitionsBrowsers

Support level 1

Supported web browser

  • All content MUST be readable and useable and all functionality MUST work;
  • Variations to presentation of content MUST be minimised;
  • Where CSS layout is used, the CSS MUST be rendered by supported web browsers, so that a fully-styled version of the page is presented to the user;
  • Internet Explorer 8, 9, 11
  • Chrome 32
  • Firefox 26, 27
  • Safari 7

Support level 2

Partially-supported web browser

  • All core content MUST be readable and usable and navigation MUST work;
  • Any degradation to (client-side) application functionality MUST be graceful degradation;
  • Any degradation to presentation MUST NOT obscure content;
  • Where CSS layout is used, an unstyled version of the page may be provided to a partially-supported browser.
  • Internet Explorer 7, 10
  • Safari 5, 6 
  • Chrome 33

Support level 3

Unsupported web browser

  • No support or testing necessary.
  • All web browsers not specifically listed in the support levels 1 and 2 are unsupported.
  • Internet Explorer 6 and earlier
  • Firefox 25 and earlier
  • Chrome 31 and earlier
  • Opera (any version)

Note: We do not support Beta versions of any web browser.

Decision tree

Probably level 3

  • Browser is not actively supported by the manufacturer; or
  • less than 1% of site users; or
  • upgrade has been available for more than 3 years and less than 2% of users; or
  • significantly behind standards or adds significantly to development time and less than 2.5% of users; or
  • new browser and less than 5% of site users.

Probably level 2

  • Less than 2% of site users; or
  • upgrade has been available for more than 3 years and less than 4% of users; or
  • significantly behind standards or adds significantly to development time and less than 5% of users.

Probably level 1

  • All of the above statements are not true; or
  • strategically supported browser; or
  • new browser and more than 5% of site users.

Last updated: 5 March 2014