Forecast · Ireland

Sky Colour Forecast

Likelihood of a colourful sunrise or sunset across Ireland, built from a 3-model average of cloud/humidity fields (ECMWF, GFS, ICON), CAMS aerosol data, and the forecasting method in Mastering the Prediction of Sunrises & Sunsets.

Hover or tap a point for the forecast at that spot.
Unlikely
Exceptional

This is a projection based on NWP (numerical weather prediction) model output only — it is no guarantee that you will see a colourful sky. For your own predictions, refer to Mastering the Prediction of Sunrises & Sunsets by Sryan Bruen — human interpretation will almost always beat direct NWP output.

How this forecast is built ▸

Data

Hourly cloud cover (low/mid/high), 2 m humidity and 10 m wind are pulled from three independent forecast models — ECMWF IFS, NOAA GFS and DWD ICON — and averaged per field, so no single model's error drives the score alone; aerosol optical depth, PM2.5/PM10 and dust are pulled from Copernicus CAMS — all via the Open‑Meteo API, on a 72‑point grid across Ireland. Where the three models disagree substantially on cloud cover at a point, that's flagged and named in its reasoning text rather than smoothed away silently. Sunrise/sunset times and sun azimuth are computed astronomically for each grid point and day.

Score components

  • Horizon clarity — how clear the sky is right in the sun's direction (west at sunset, east at sunrise), using cloud at the point itself and its neighbour towards the horizon. Thick low cloud there blocks the show.
  • Colour canvas — the point's own mid/high cloud cover. A moderate, broken amount catches and scatters light best; a solid overcast mutes it through multiple scattering; a fully clear sky gets a moderate baseline (a golden horizon glow, but no dramatic overhead colour).
  • Afterglow — moderate mid/high cloud on the far side of the sky, which can light up after the sun has set or before it rises.

Adjustments

  • Humidity — low humidity boosts the score (saturated colour); high humidity (haze/mist) mutes it.
  • Haze/aerosols — a little haze can warm up the disc and horizon; a lot washes everything out or blocks it entirely. Saharan dust is flagged separately as it can go either way.
  • Wind direction — each compass sector carries the tendencies set out in the book (e.g. south-easterlies import the most pollution; north-westerlies bring showery breaks good for sunset colour).
  • Fog/mist risk — flagged when winds are light and air is near-saturated; a genuine gamble either way.

Limitations

Grid points sit roughly 45–65 km apart, coarser than the underlying weather models themselves, so hyper-local effects (a single valley, a specific headland) won't be captured exactly. A low score means unlikely, not impossible — especially where the models disagree with each other, a brief break in the cloud can still produce some colour. This is a single forecast-run snapshot, not a live feed — ask for a refresh to regenerate it against the latest model run.

Methodology adapted from Mastering the Prediction of Sunrises & Sunsets by Sryan Bruen. Weather data: ECMWF IFS, NOAA GFS & DWD ICON (averaged), plus Copernicus CAMS, via Open‑Meteo.