{"assessment":{"best_window":null,"cost":{"altitude":0.0,"clouds":8.03,"darkness":2.52,"moon":1.87},"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 8.8 of 11.8 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Barely","hourly":[{"alt":null,"cloud":100,"high":99,"iso":"2025-10-13T16:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-23,"precip":0.1,"q":0.0,"rh":96,"sky":"civil twilight","temp":4.5,"time":"19:00","wind":3.3},{"alt":null,"cloud":100,"high":100,"iso":"2025-10-13T17:00Z","label":"unusable","low":100,"mid":1,"moon_alt":-22,"precip":0.1,"q":0.0,"rh":92,"sky":"astronomical twilight","temp":5.0,"time":"20:00","wind":1.1},{"alt":null,"cloud":100,"high":96,"iso":"2025-10-13T18:00Z","label":"unusable","low":100,"mid":1,"moon_alt":-19,"precip":0.0,"q":0.0,"rh":92,"sky":"night","temp":4.9,"time":"21:00","wind":1.3},{"alt":null,"cloud":91,"high":0,"iso":"2025-10-13T19:00Z","label":"unusable","low":90,"mid":1,"moon_alt":-14,"precip":0.0,"q":0.0,"rh":93,"sky":"night","temp":4.4,"time":"22:00","wind":2.2},{"alt":null,"cloud":73,"high":1,"iso":"2025-10-13T20:00Z","label":"poor","low":73,"mid":1,"moon_alt":-7,"precip":0.0,"q":0.19,"rh":93,"sky":"night","temp":3.5,"time":"23:00","wind":1.4},{"alt":null,"cloud":66,"high":0,"iso":"2025-10-13T21:00Z","label":"poor","low":65,"mid":1,"moon_alt":1,"precip":0.0,"q":0.21,"rh":91,"sky":"night","temp":3.5,"time":"00:00","wind":0.4},{"alt":null,"cloud":78,"high":0,"iso":"2025-10-13T22:00Z","label":"poor","low":78,"mid":1,"moon_alt":10,"precip":0.0,"q":0.1,"rh":92,"sky":"night","temp":3.2,"time":"01:00","wind":0.5},{"alt":null,"cloud":91,"high":0,"iso":"2025-10-13T23:00Z","label":"unusable","low":91,"mid":1,"moon_alt":20,"precip":0.0,"q":0.0,"rh":91,"sky":"night","temp":3.3,"time":"02:00","wind":0.7},{"alt":null,"cloud":100,"high":0,"iso":"2025-10-14T00:00Z","label":"unusable","low":100,"mid":0,"moon_alt":31,"precip":0.0,"q":0.0,"rh":94,"sky":"night","temp":1.9,"time":"03:00","wind":0.8},{"alt":null,"cloud":100,"high":0,"iso":"2025-10-14T01:00Z","label":"unusable","low":100,"mid":0,"moon_alt":42,"precip":0.0,"q":0.0,"rh":94,"sky":"night","temp":1.5,"time":"04:00","wind":0.4},{"alt":null,"cloud":100,"high":0,"iso":"2025-10-14T02:00Z","label":"unusable","low":100,"mid":0,"moon_alt":52,"precip":0.0,"q":0.0,"rh":93,"sky":"night","temp":2.6,"time":"05:00","wind":0.0},{"alt":null,"cloud":100,"high":0,"iso":"2025-10-14T03:00Z","label":"unusable","low":100,"mid":0,"moon_alt":63,"precip":0.0,"q":0.0,"rh":93,"sky":"astronomical twilight","temp":2.7,"time":"06:00","wind":0.6},{"alt":null,"cloud":100,"high":0,"iso":"2025-10-14T04:00Z","label":"unusable","low":100,"mid":1,"moon_alt":70,"precip":0.0,"q":0.0,"rh":94,"sky":"nautical twilight","temp":2.9,"time":"07:00","wind":1.8}],"peak_quality":0.21,"peak_sky":1.0,"quality_hours":0.5,"reasons":["cloud cover cost 8.0 quality-hours","daylight and twilight cost 2.5 quality-hours","moonlight cost 1.9 quality-hours"],"reference_hours":4.0,"score":6,"score_astronomy":100,"score_weather":6,"sky_hours":8.53,"verdict":"poor","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2025-10-13T20:00Z","end_local":"23:00","hours":4.33,"label":"unusable","mean_quality":0.0,"start":"2025-10-13T15:40Z","start_local":"18:40"},{"end":"2025-10-13T23:00Z","end_local":"02:00","hours":3.0,"label":"poor","mean_quality":0.17,"start":"2025-10-13T20:00Z","start_local":"23:00"},{"end":"2025-10-14T04:35Z","end_local":"07:35","hours":5.58,"label":"unusable","mean_quality":0.0,"start":"2025-10-13T23:00Z","start_local":"02:00"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":100,"dark":false,"high":100,"local":"18:00","low":100,"mid":0,"precip":0.1,"rh":85,"temp":6.1,"time":"2025-10-13T15:00Z","wind":6.6},{"cloud":100,"dark":false,"high":99,"local":"19:00","low":100,"mid":0,"precip":0.1,"rh":96,"temp":4.5,"time":"2025-10-13T16:00Z","wind":3.3},{"cloud":100,"dark":false,"high":100,"local":"20:00","low":100,"mid":1,"precip":0.1,"rh":92,"temp":5.0,"time":"2025-10-13T17:00Z","wind":1.1},{"cloud":100,"dark":true,"high":96,"local":"21:00","low":100,"mid":1,"precip":0.0,"rh":92,"temp":4.9,"time":"2025-10-13T18:00Z","wind":1.3},{"cloud":91,"dark":true,"high":0,"local":"22:00","low":90,"mid":1,"precip":0.0,"rh":93,"temp":4.4,"time":"2025-10-13T19:00Z","wind":2.2},{"cloud":73,"dark":true,"high":1,"local":"23:00","low":73,"mid":1,"precip":0.0,"rh":93,"temp":3.5,"time":"2025-10-13T20:00Z","wind":1.4},{"cloud":66,"dark":true,"high":0,"local":"00:00","low":65,"mid":1,"precip":0.0,"rh":91,"temp":3.5,"time":"2025-10-13T21:00Z","wind":0.4},{"cloud":78,"dark":true,"high":0,"local":"01:00","low":78,"mid":1,"precip":0.0,"rh":92,"temp":3.2,"time":"2025-10-13T22:00Z","wind":0.5},{"cloud":91,"dark":true,"high":0,"local":"02:00","low":91,"mid":1,"precip":0.0,"rh":91,"temp":3.3,"time":"2025-10-13T23:00Z","wind":0.7},{"cloud":100,"dark":true,"high":0,"local":"03:00","low":100,"mid":0,"precip":0.0,"rh":94,"temp":1.9,"time":"2025-10-14T00:00Z","wind":0.8},{"cloud":100,"dark":true,"high":0,"local":"04:00","low":100,"mid":0,"precip":0.0,"rh":94,"temp":1.5,"time":"2025-10-14T01:00Z","wind":0.4},{"cloud":100,"dark":true,"high":0,"local":"05:00","low":100,"mid":0,"precip":0.0,"rh":93,"temp":2.6,"time":"2025-10-14T02:00Z","wind":0.0},{"cloud":100,"dark":false,"high":0,"local":"06:00","low":100,"mid":0,"precip":0.0,"rh":93,"temp":2.7,"time":"2025-10-14T03:00Z","wind":0.6},{"cloud":100,"dark":false,"high":0,"local":"07:00","low":100,"mid":1,"precip":0.0,"rh":94,"temp":2.9,"time":"2025-10-14T04:00Z","wind":1.8},{"cloud":100,"dark":false,"high":4,"local":"08:00","low":100,"mid":0,"precip":0.0,"rh":92,"temp":3.1,"time":"2025-10-14T05:00Z","wind":1.6}],"forecast_source":"history","forecast_updated_at":"2026-10-22T00:09:45Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2025-10-13T17:15:03Z","dark_hours":9.74,"dark_to":"2025-10-14T02:59:43Z","moon":{"illumination":0.482,"phase":"last quarter","waxing":false},"moon_free_dark_hours":3.63,"moonrise":"2025-10-13T20:54:05Z","moonset":"2025-10-13T11:48:22Z","sunrise":"2025-10-14T04:32:07Z","sunset":"2025-10-13T15:42:50Z","twilight":{"astronomical":{"end":"2025-10-13T17:15:03Z","start":"2025-10-14T02:59:43Z"},"civil":{"end":"2025-10-13T16:10:45Z","start":"2025-10-14T04:04:08Z"},"nautical":{"end":"2025-10-13T16:42:54Z","start":"2025-10-14T03:31:55Z"}},"window_end":"2025-10-14T09:00:00Z","window_start":"2025-10-13T09:00:00Z"},"night_date":"2025-10-13","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}