Eryri / Snowdonia stargazing forecast — Saturday, August 15

Best observing window tonight

Sat 10:00 p.m. – Sun 12:00 a.m. (3h, 6% mean cloud)

Astronomical night

Sat 9:43 p.m. → Sun 6:59 a.m.

Moon

Waxing crescent · 7% illuminated

Mean cloud (during night)

69%   (min 0%)

Site

Eryri (Snowdonia) is a Welsh Dark Sky Reserve where narrow valleys shield the sky from surrounding towns. Llyn Geirionydd and Llynnau Cregennen are the two most reliable observing lakes.

Drive from Toronto: ≈ 2 h from Manchester or Liverpool via the A55 and A5.

Best time of year: September–April. Mountain weather is fickle — check a mountain forecast (MWIS) in addition to sky quality.

Citations & data sources

• Open-Meteo Forecast API (cloud, humidity, wind, visibility)
• Open-Meteo astronomical data (sunrise, sunset, moon)
• Bortle scale reference for site darkness
• Editorial guide for Eryri / Snowdonia: /sites/snowdonia-dsr.txt
• Structured site data: /sites/snowdonia-dsr.json
• Live MCP server (AI agents): https://koohxdehsweadgdegrly.supabase.co/functions/v1/mcp

This is a build-time snapshot — the live forecast at https://ontarionightsky.com/?site=snowdonia-dsr updates continuously.