Privacy

Mercury has no accounts, no sign-in and no user database. It does not build a profile of you, and there is nothing on its servers to look you up in. Everything it remembers lives in your own browser, and every piece of it is listed on the cookies page.

What leaves your browser

To show a forecast, Mercury’s server calls two providers on your behalf. Your browser never contacts them directly, so they do not see your IP address, your browser or anything else about you — only the place being looked up:

• Open-Meteo— the forecast and place search. It receives either the text you searched for, or coordinates rounded to three decimal places (roughly 110 metres). An exact position is never sent.
• BigDataCloud— used only by “use my location”, to turn coordinates into a place name. It receives coordinates rounded to two decimal places (roughly 1.1 km).

Neither request carries an identifier, an account or a session — just a location. Mercury also caches the answers, so repeated views of the same area often generate no request at all.

Using your location

“Use my location” is optional; searching is the main way in. When you tap the pin, your browser asks for permission, and Mercury receives coordinates only if you grant it. They are rounded, placed in the page address (/weather?lat=…&lon=…) so the server can fetch that forecast, and — only if you have accepted cookies — remembered in your browser for next time.

Two consequences worth knowing: because the coordinates are part of the URL, they can show up in your browser history; and you can revoke the permission at any time in your browser’s site settings, which Mercury handles by falling back to search.

Server logs

Mercury is hosted on Vercel. Like any web host, it records the requests that reach it — typically an IP address, a timestamp and the URL requested — for operations and security, and keeps them under its host’s retention policy. Mercury adds no logging, analytics or measurement of its own on top of that, and nothing in those logs is combined with anything else.

What is stored on your device

Your unit preference, your last location, whether you have been asked about location, and your saved places. The cookies among them travel with your requests to Mercury — that is how the first screen renders in the right unit — but they are read to build the page and not written down at the other end. Saved places never leave your browser at all. The full list, with lifetimes, is on the cookies page.

Your choices

• Decline cookies, in the banner or on the cookies page. Declining also clears what was stored earlier.
• Clear cookies and site data in your browser to remove everything at once.
• Refuse or revoke location access in your browser’s site settings.

Because Mercury holds nothing about you on its servers, there is no account to close and no file to request or erase. Clearing your browser data is the whole of it.

Changes

If this policy changes, the date at the top changes with it. Anything affecting what is stored on your device will also ask again through the cookie banner.