About The Almanac

An almanac, made live and local: a small site that takes a question people have about a place (is there water at the steps, can I see the mountain) and answers it from public data, with the workings shown. It is a static site, rebuilt every morning at about 03:00 Irish time; the live parts run in your browser.

How it works

Tide times are computed from harmonic constants fitted to the Marine Institute's published predictions, so your phone works the tide out itself and it keeps working with no signal. Weather, sea temperature and the mountain verdict are fetched by your browser from the services below when the page opens. The tables, verdict snapshots and text on each page are also written into the page when it is built, labelled with the time they were made.

Every number is an estimate with a method behind it, and each place page says how it is worked out, where it could be wrong, and how to tell us. Folklore is labelled as folklore.

Sources and licences

• Tide predictions: Marine Institute predictions for Roonagh (CC BY 4.0), fitted here and computed in your browser; contains Irish Public Sector Data.
• Sea temperature: Marine Institute NE Atlantic model and Irish Coastal Temperature Network (CC BY 4.0); Météo-France sea-surface temperature via Open-Meteo.
• Weather: Weather data by Open-Meteo.com (CC BY 4.0), fetched by your browser.
• LiDAR: contains Irish Public Sector Data (Geological Survey Ireland; Office of Public Works 2011 survey) licensed under CC BY 4.0.
• Bathymetry: contains Irish Public Sector Data (Geological Survey Ireland & Marine Institute, INFOMAR) licensed under CC BY 4.0.
• Flood maps: Office of Public Works, floodinfo.ie (CC BY-NC-ND 4.0): quoted, not reproduced.
• Sea-level projections: IPCC AR6 (Fox-Kemper et al. 2021; Garner et al. 2021, doi:10.5281/zenodo.5914709; Kopp et al. 2023) via the NASA Sea Level Projection Tool, CC BY 4.0.
• Map data: © OpenStreetMap contributors, ODbL.
• Elevation: AWS Terrain Tiles (Mapzen/Tilezen): Europe terrain data produced using Copernicus data and information funded by the European Union - EU-DEM layers; ETOPO1, U.S. National Oceanic and Atmospheric Administration; GMTED2010 and SRTM courtesy of the U.S. Geological Survey.
• Map tiles: OpenFreeMap © OpenMapTiles, data from OpenStreetMap; MapLibre GL JS (BSD-3-Clause).
• Irish names: Irish-language placename data by Logainm © Government of Ireland and licensed under CC BY 4.0.

Each page also carries its own numbered list of sources for the facts it states. Quotations are short and credited.

Data files on this site that are derived from OpenStreetMap (the places, peaks and skyline features behind the Croagh Patrick page, and the map of the Point) are made available under the Open Database License.

Sea-level projections: we thank the projection authors for developing and making the sea-level rise projections available, multiple funding agencies for supporting the development of the projections, and the NASA Sea Level Change Team for developing and hosting the IPCC AR6 Sea Level Projection Tool.

Fonts: Fraunces and Inter, SIL Open Font License 1.1 (licence, licence).

Privacy

No cookies, no analytics, no accounts, no ads. Your browser talks directly to Open-Meteo and the Marine Institute for forecasts; on the mountain page, the map loads tiles from OpenFreeMap, the map library from unpkg.com, and elevation tiles from Amazon's open-data bucket. Those services see your IP address, as any website you visit would. Anything you log on a page (dips, sightings, a correction) is kept in your browser's local storage on your device and is never sent anywhere; export and import are files you move yourself.

Safety

Depths, tides and cloud verdicts here are predictions and estimates, not measurements. There are no lifeguards at the swim spots unless the local council says so. Look for yourself before you go in or go up.

Corrections

If you know better (the year the steps were built, what your granny called the hill), that is exactly what these pages want to hear. A contact address is coming with the domain. On the swim pages, "Tell us where the water was" checks the model against what you saw.