{"assessment":{"best_window":null,"cost":{"altitude":0.0,"clouds":4.99,"darkness":3.05,"moon":0.89},"formula":"astronomy = 100 * min(1, sky_hours / reference_hours) * peak_sky; overall = astronomy * score_weather / 100 (null when the weather is unknown)","hard_limit":"Overcast (\u226580 % cloud) for 6.2 of 8.2 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Barely","hourly":[{"alt":null,"cloud":88,"high":74,"iso":"2026-05-22T18:00Z","label":"unusable","low":44,"mid":42,"moon_alt":52,"precip":0.3,"q":0.0,"rh":100,"sky":"civil twilight","temp":6.6,"time":"21:00","wind":9.3},{"alt":null,"cloud":70,"high":40,"iso":"2026-05-22T19:00Z","label":"poor","low":48,"mid":8,"moon_alt":43,"precip":0.3,"q":0.08,"rh":100,"sky":"astronomical twilight","temp":6.4,"time":"22:00","wind":9.0},{"alt":null,"cloud":84,"high":46,"iso":"2026-05-22T20:00Z","label":"unusable","low":70,"mid":5,"moon_alt":32,"precip":0.1,"q":0.0,"rh":99,"sky":"night","temp":6.4,"time":"23:00","wind":9.5},{"alt":null,"cloud":85,"high":59,"iso":"2026-05-22T21:00Z","label":"unusable","low":50,"mid":28,"moon_alt":21,"precip":0.1,"q":0.0,"rh":99,"sky":"night","temp":6.5,"time":"00:00","wind":9.3},{"alt":null,"cloud":66,"high":12,"iso":"2026-05-22T22:00Z","label":"poor","low":41,"mid":38,"moon_alt":10,"precip":0.6,"q":0.21,"rh":99,"sky":"night","temp":6.3,"time":"01:00","wind":8.5},{"alt":null,"cloud":80,"high":62,"iso":"2026-05-22T23:00Z","label":"unusable","low":42,"mid":15,"moon_alt":-1,"precip":0.5,"q":0.0,"rh":99,"sky":"night","temp":6.0,"time":"02:00","wind":10.6},{"alt":null,"cloud":88,"high":46,"iso":"2026-05-23T00:00Z","label":"unusable","low":73,"mid":20,"moon_alt":-11,"precip":0.1,"q":0.0,"rh":99,"sky":"night","temp":5.7,"time":"03:00","wind":8.9},{"alt":null,"cloud":100,"high":100,"iso":"2026-05-23T01:00Z","label":"unusable","low":96,"mid":31,"moon_alt":-20,"precip":0.6,"q":0.0,"rh":99,"sky":"astronomical twilight","temp":5.6,"time":"04:00","wind":8.9},{"alt":null,"cloud":100,"high":95,"iso":"2026-05-23T02:00Z","label":"unusable","low":100,"mid":16,"moon_alt":-28,"precip":1.1,"q":0.0,"rh":99,"sky":"nautical twilight","temp":6.4,"time":"05:00","wind":10.3}],"peak_quality":0.22,"peak_sky":1.0,"quality_hours":0.31,"reasons":["cloud cover cost 5.0 quality-hours","daylight and twilight cost 3.1 quality-hours","moonlight cost 0.9 quality-hours"],"reference_hours":4.0,"score":6,"score_astronomy":100,"score_weather":6,"sky_hours":5.31,"verdict":"poor","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-05-22T19:00Z","end_local":"22:00","hours":1.33,"label":"unusable","mean_quality":0.0,"start":"2026-05-22T17:40Z","start_local":"20:40"},{"end":"2026-05-22T20:00Z","end_local":"23:00","hours":1.0,"label":"poor","mean_quality":0.1,"start":"2026-05-22T19:00Z","start_local":"22:00"},{"end":"2026-05-22T22:00Z","end_local":"01:00","hours":2.0,"label":"unusable","mean_quality":0.0,"start":"2026-05-22T20:00Z","start_local":"23:00"},{"end":"2026-05-22T23:00Z","end_local":"02:00","hours":1.0,"label":"poor","mean_quality":0.22,"start":"2026-05-22T22:00Z","start_local":"01:00"},{"end":"2026-05-23T02:55Z","end_local":"05:55","hours":3.92,"label":"unusable","mean_quality":0.0,"start":"2026-05-22T23:00Z","start_local":"02:00"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":66,"dark":false,"high":54,"local":"20:00","low":16,"mid":22,"precip":0.9,"rh":98,"temp":7.5,"time":"2026-05-22T17:00Z","wind":9.8},{"cloud":88,"dark":false,"high":74,"local":"21:00","low":44,"mid":42,"precip":0.3,"rh":100,"temp":6.6,"time":"2026-05-22T18:00Z","wind":9.3},{"cloud":70,"dark":false,"high":40,"local":"22:00","low":48,"mid":8,"precip":0.3,"rh":100,"temp":6.4,"time":"2026-05-22T19:00Z","wind":9.0},{"cloud":84,"dark":true,"high":46,"local":"23:00","low":70,"mid":5,"precip":0.1,"rh":99,"temp":6.4,"time":"2026-05-22T20:00Z","wind":9.5},{"cloud":85,"dark":true,"high":59,"local":"00:00","low":50,"mid":28,"precip":0.1,"rh":99,"temp":6.5,"time":"2026-05-22T21:00Z","wind":9.3},{"cloud":66,"dark":true,"high":12,"local":"01:00","low":41,"mid":38,"precip":0.6,"rh":99,"temp":6.3,"time":"2026-05-22T22:00Z","wind":8.5},{"cloud":80,"dark":true,"high":62,"local":"02:00","low":42,"mid":15,"precip":0.5,"rh":99,"temp":6.0,"time":"2026-05-22T23:00Z","wind":10.6},{"cloud":88,"dark":true,"high":46,"local":"03:00","low":73,"mid":20,"precip":0.1,"rh":99,"temp":5.7,"time":"2026-05-23T00:00Z","wind":8.9},{"cloud":100,"dark":false,"high":100,"local":"04:00","low":96,"mid":31,"precip":0.6,"rh":99,"temp":5.6,"time":"2026-05-23T01:00Z","wind":8.9},{"cloud":100,"dark":false,"high":95,"local":"05:00","low":100,"mid":16,"precip":1.1,"rh":99,"temp":6.4,"time":"2026-05-23T02:00Z","wind":10.3},{"cloud":100,"dark":false,"high":55,"local":"06:00","low":100,"mid":18,"precip":0.2,"rh":99,"temp":6.8,"time":"2026-05-23T03:00Z","wind":9.4}],"forecast_source":"history","forecast_updated_at":"2026-10-13T18:24:25Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-05-22T19:40:58Z","dark_hours":5.22,"dark_to":"2026-05-23T00:54:15Z","moon":{"illumination":0.442,"phase":"waxing crescent","waxing":true},"moon_free_dark_hours":1.97,"moonrise":null,"moonset":"2026-05-22T22:55:18Z","sunrise":"2026-05-23T02:54:37Z","sunset":"2026-05-22T17:40:36Z","twilight":{"astronomical":{"end":"2026-05-22T19:40:58Z","start":"2026-05-23T00:54:15Z"},"civil":{"end":"2026-05-22T18:13:07Z","start":"2026-05-23T02:22:05Z"},"nautical":{"end":"2026-05-22T18:54:03Z","start":"2026-05-23T01:41:10Z"}},"window_end":"2026-05-23T09:00:00Z","window_start":"2026-05-22T09:00:00Z"},"night_date":"2026-05-22","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
