Cookies

What Mercury keeps in your browser, and how to stop it.

Last updated 22 August 2026

Mercury has no accounts, no analytics and no advertising. What it keeps in your browser is there for one reason: so the app looks the way you left it. This page lists every item, what it does, and how long it lasts.

Nothing below is stored until you accept.Before you answer the banner — and after a refusal — Mercury neither writes nor reads any of it. The app still works; it simply doesn’t remember anything between visits.

What Mercury stores

  • mercury-consentCookie · 1 year

    Your answer to the cookie banner. This is the only thing Mercury sets before you have chosen, and it is what makes the choice stick: without it, the banner would have to ask again on every page you open.

  • mercury-unitsCookie · 1 year

    Whether you read temperatures in °C or °F. A cookie rather than browser storage, so the server can render the first screen in the unit you chose instead of flashing the wrong one and correcting itself.

  • mercury-placeCookie · 1 year

    The last location you looked up — its coordinates and name — so Mercury opens where you left off rather than on its default city.

  • mercury-geo-askedCookie · 1 year

    A single flag noting that you have already been asked for location access, so you are not asked again on every visit.

  • mercury-bookmarksLocal storage · Until cleared

    Your saved locations: names and coordinates only, never weather data. Local storage rather than a cookie, so a growing list is not attached to every request your browser makes.

What Mercury does not do

  • No analytics, advertising, tracking or profiling of any kind.
  • No third-party cookies. Everything above is set by Mercury itself.
  • Nothing is sold or shared. These values are read by Mercury alone.

If you decline

The app keeps working — it just stops remembering. Temperatures start in °C each visit, Mercury opens on its default city instead of your last location, and saved places last only until you close the tab. Declining also clears anything stored earlier, so it is not only a rule for the future.

One knock-on effect: Mercury will not offer to use your location automatically, because it has nowhere to record that it already asked. The pin button in the search bar still works whenever you want it.

Changing your mind

You can switch at any time, and it takes effect immediately — declining here clears what is stored right away.

You can also clear cookies and site data for this site in your browser’s settings. That removes everything on this page, including the record of your choice, so Mercury will ask again on your next visit.

Location is separate

Access to your location is a browser permission rather than a cookie, and Mercury asks for it separately, only when you use it. What happens to those coordinates — and what reaches the two providers Mercury relies on — is covered in the privacy policy.