{"assessment":{"best_window":{"end":"2025-08-01T01:25Z","end_local":"04:25","hours":0.42,"label":"good","mean_quality":0.62,"start":"2025-08-01T01:00Z","start_local":"04:00"},"cost":{"altitude":0.0,"clouds":5.89,"darkness":3.02,"moon":0.29},"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 6.7 of 8.5 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Barely","hourly":[{"alt":null,"cloud":100,"high":100,"iso":"2025-07-31T18:00Z","label":"unusable","low":39,"mid":100,"moon_alt":23,"precip":2.3,"q":0.0,"rh":99,"sky":"civil twilight","temp":11.9,"time":"21:00","wind":4.8},{"alt":null,"cloud":100,"high":100,"iso":"2025-07-31T19:00Z","label":"unusable","low":35,"mid":100,"moon_alt":15,"precip":1.7,"q":0.0,"rh":100,"sky":"astronomical twilight","temp":11.5,"time":"22:00","wind":5.6},{"alt":null,"cloud":100,"high":100,"iso":"2025-07-31T20:00Z","label":"unusable","low":41,"mid":92,"moon_alt":6,"precip":0.7,"q":0.0,"rh":100,"sky":"night","temp":11.0,"time":"23:00","wind":6.1},{"alt":null,"cloud":98,"high":87,"iso":"2025-07-31T21:00Z","label":"unusable","low":39,"mid":91,"moon_alt":-5,"precip":0.1,"q":0.0,"rh":100,"sky":"night","temp":10.7,"time":"00:00","wind":5.1},{"alt":null,"cloud":94,"high":69,"iso":"2025-07-31T22:00Z","label":"unusable","low":32,"mid":88,"moon_alt":-15,"precip":0.0,"q":0.0,"rh":100,"sky":"night","temp":10.3,"time":"01:00","wind":6.0},{"alt":null,"cloud":84,"high":1,"iso":"2025-07-31T23:00Z","label":"unusable","low":50,"mid":71,"moon_alt":-26,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":9.9,"time":"02:00","wind":5.0},{"alt":null,"cloud":81,"high":0,"iso":"2025-08-01T00:00Z","label":"unusable","low":43,"mid":71,"moon_alt":-37,"precip":0.0,"q":0.0,"rh":100,"sky":"night","temp":9.7,"time":"03:00","wind":5.3},{"alt":null,"cloud":34,"high":0,"iso":"2025-08-01T01:00Z","label":"good","low":34,"mid":1,"moon_alt":-48,"precip":0.0,"q":0.62,"rh":99,"sky":"night","temp":9.0,"time":"04:00","wind":5.2},{"alt":null,"cloud":32,"high":0,"iso":"2025-08-01T02:00Z","label":"marginal","low":29,"mid":10,"moon_alt":-57,"precip":0.0,"q":0.32,"rh":99,"sky":"astronomical twilight","temp":9.3,"time":"05:00","wind":5.9},{"alt":null,"cloud":25,"high":0,"iso":"2025-08-01T03:00Z","label":"unusable","low":24,"mid":5,"moon_alt":-63,"precip":0.0,"q":0.0,"rh":99,"sky":"civil twilight","temp":8.8,"time":"06:00","wind":5.0}],"peak_quality":0.62,"peak_sky":1.0,"quality_hours":0.55,"reasons":["cloud cover cost 5.9 quality-hours","daylight and twilight cost 3.0 quality-hours"],"reference_hours":4.0,"score":9,"score_astronomy":100,"score_weather":9,"sky_hours":6.44,"verdict":"poor","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2025-08-01T01:00Z","end_local":"04:00","hours":7.42,"label":"unusable","mean_quality":0.0,"start":"2025-07-31T17:35Z","start_local":"20:35"},{"end":"2025-08-01T01:25Z","end_local":"04:25","hours":0.42,"label":"good","mean_quality":0.62,"start":"2025-08-01T01:00Z","start_local":"04:00"},{"end":"2025-08-01T02:10Z","end_local":"05:10","hours":0.75,"label":"marginal","mean_quality":0.31,"start":"2025-08-01T01:25Z","start_local":"04:25"},{"end":"2025-08-01T02:45Z","end_local":"05:45","hours":0.58,"label":"poor","mean_quality":0.1,"start":"2025-08-01T02:10Z","start_local":"05:10"},{"end":"2025-08-01T03:20Z","end_local":"06:20","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2025-08-01T02:45Z","start_local":"05:45"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":100,"dark":false,"high":99,"local":"20:00","low":33,"mid":96,"precip":0.2,"rh":89,"temp":12.9,"time":"2025-07-31T17:00Z","wind":5.4},{"cloud":100,"dark":false,"high":100,"local":"21:00","low":39,"mid":100,"precip":2.3,"rh":99,"temp":11.9,"time":"2025-07-31T18:00Z","wind":4.8},{"cloud":100,"dark":false,"high":100,"local":"22:00","low":35,"mid":100,"precip":1.7,"rh":100,"temp":11.5,"time":"2025-07-31T19:00Z","wind":5.6},{"cloud":100,"dark":true,"high":100,"local":"23:00","low":41,"mid":92,"precip":0.7,"rh":100,"temp":11.0,"time":"2025-07-31T20:00Z","wind":6.1},{"cloud":98,"dark":true,"high":87,"local":"00:00","low":39,"mid":91,"precip":0.1,"rh":100,"temp":10.7,"time":"2025-07-31T21:00Z","wind":5.1},{"cloud":94,"dark":true,"high":69,"local":"01:00","low":32,"mid":88,"precip":0.0,"rh":100,"temp":10.3,"time":"2025-07-31T22:00Z","wind":6.0},{"cloud":84,"dark":true,"high":1,"local":"02:00","low":50,"mid":71,"precip":0.0,"rh":99,"temp":9.9,"time":"2025-07-31T23:00Z","wind":5.0},{"cloud":81,"dark":true,"high":0,"local":"03:00","low":43,"mid":71,"precip":0.0,"rh":100,"temp":9.7,"time":"2025-08-01T00:00Z","wind":5.3},{"cloud":34,"dark":true,"high":0,"local":"04:00","low":34,"mid":1,"precip":0.0,"rh":99,"temp":9.0,"time":"2025-08-01T01:00Z","wind":5.2},{"cloud":32,"dark":false,"high":0,"local":"05:00","low":29,"mid":10,"precip":0.0,"rh":99,"temp":9.3,"time":"2025-08-01T02:00Z","wind":5.9},{"cloud":25,"dark":false,"high":0,"local":"06:00","low":24,"mid":5,"precip":0.0,"rh":99,"temp":8.8,"time":"2025-08-01T03:00Z","wind":5.0},{"cloud":15,"dark":false,"high":0,"local":"07:00","low":14,"mid":5,"precip":0.0,"rh":98,"temp":9.3,"time":"2025-08-01T04:00Z","wind":6.4}],"forecast_source":"history","forecast_updated_at":"2026-10-24T13:44:38Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2025-07-31T19:33:28Z","dark_hours":5.81,"dark_to":"2025-08-01T01:21:46Z","moon":{"illumination":0.444,"phase":"waxing crescent","waxing":true},"moon_free_dark_hours":4.8,"moonrise":"2025-07-31T10:11:07Z","moonset":"2025-07-31T20:32:04Z","sunrise":"2025-08-01T03:15:20Z","sunset":"2025-07-31T17:39:56Z","twilight":{"astronomical":{"end":"2025-07-31T19:33:28Z","start":"2025-08-01T01:21:46Z"},"civil":{"end":"2025-07-31T18:11:16Z","start":"2025-08-01T02:43:59Z"},"nautical":{"end":"2025-07-31T18:50:08Z","start":"2025-08-01T02:05:06Z"}},"window_end":"2025-08-01T09:00:00Z","window_start":"2025-07-31T09:00:00Z"},"night_date":"2025-07-31","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
