{"assessment":{"best_window":null,"cost":{"altitude":0.0,"clouds":8.24,"darkness":2.55,"moon":3.05},"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 12.8 of 12.8 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Not tonight","hourly":[{"alt":null,"cloud":97,"high":61,"iso":"2026-02-06T16:00Z","label":"unusable","low":53,"mid":81,"moon_alt":-50,"precip":0.0,"q":0.0,"rh":97,"sky":"civil twilight","temp":-1.0,"time":"18:00","wind":6.1},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-06T17:00Z","label":"unusable","low":62,"mid":97,"moon_alt":-41,"precip":0.0,"q":0.0,"rh":98,"sky":"astronomical twilight","temp":-1.8,"time":"19:00","wind":5.0},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-06T18:00Z","label":"unusable","low":63,"mid":99,"moon_alt":-32,"precip":0.0,"q":0.0,"rh":100,"sky":"night","temp":-1.0,"time":"20:00","wind":7.5},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-06T19:00Z","label":"unusable","low":46,"mid":99,"moon_alt":-21,"precip":0.0,"q":0.0,"rh":100,"sky":"night","temp":-1.5,"time":"21:00","wind":7.2},{"alt":null,"cloud":95,"high":16,"iso":"2026-02-06T20:00Z","label":"unusable","low":94,"mid":15,"moon_alt":-10,"precip":0.0,"q":0.0,"rh":100,"sky":"night","temp":-1.5,"time":"22:00","wind":7.7},{"alt":null,"cloud":100,"high":0,"iso":"2026-02-06T21:00Z","label":"unusable","low":100,"mid":0,"moon_alt":0,"precip":0.0,"q":0.0,"rh":96,"sky":"night","temp":-0.5,"time":"23:00","wind":11.0},{"alt":null,"cloud":81,"high":13,"iso":"2026-02-06T22:00Z","label":"unusable","low":78,"mid":8,"moon_alt":10,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":-1.1,"time":"00:00","wind":9.1},{"alt":null,"cloud":84,"high":5,"iso":"2026-02-06T23:00Z","label":"unusable","low":83,"mid":10,"moon_alt":19,"precip":0.0,"q":0.0,"rh":100,"sky":"night","temp":-1.4,"time":"01:00","wind":8.4},{"alt":null,"cloud":86,"high":0,"iso":"2026-02-07T00:00Z","label":"unusable","low":84,"mid":12,"moon_alt":27,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":-0.5,"time":"02:00","wind":9.0},{"alt":null,"cloud":100,"high":0,"iso":"2026-02-07T01:00Z","label":"unusable","low":100,"mid":0,"moon_alt":33,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":-1.0,"time":"03:00","wind":5.8},{"alt":null,"cloud":100,"high":0,"iso":"2026-02-07T02:00Z","label":"unusable","low":100,"mid":0,"moon_alt":36,"precip":0.0,"q":0.0,"rh":100,"sky":"night","temp":-1.7,"time":"04:00","wind":5.6},{"alt":null,"cloud":100,"high":0,"iso":"2026-02-07T03:00Z","label":"unusable","low":100,"mid":0,"moon_alt":35,"precip":0.0,"q":0.0,"rh":100,"sky":"night","temp":-2.3,"time":"05:00","wind":4.9},{"alt":null,"cloud":97,"high":0,"iso":"2026-02-07T04:00Z","label":"unusable","low":97,"mid":0,"moon_alt":32,"precip":0.0,"q":0.0,"rh":99,"sky":"astronomical twilight","temp":-3.5,"time":"06:00","wind":4.0},{"alt":null,"cloud":98,"high":0,"iso":"2026-02-07T05:00Z","label":"unusable","low":97,"mid":7,"moon_alt":25,"precip":0.0,"q":0.0,"rh":98,"sky":"civil twilight","temp":-3.9,"time":"07:00","wind":4.0}],"peak_quality":0.0,"peak_sky":1.0,"quality_hours":0.0,"reasons":["cloud cover cost 8.2 quality-hours","moonlight cost 3.1 quality-hours","daylight and twilight cost 2.5 quality-hours"],"reference_hours":4.0,"score":0,"score_astronomy":100,"score_weather":0,"sky_hours":8.24,"verdict":"unusable","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-02-07T05:30Z","end_local":"07:30","hours":13.83,"label":"unusable","mean_quality":0.0,"start":"2026-02-06T15:40Z","start_local":"17:40"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":100,"dark":false,"high":72,"local":"17:00","low":45,"mid":99,"precip":0.0,"rh":89,"temp":0.2,"time":"2026-02-06T15:00Z","wind":7.3},{"cloud":97,"dark":false,"high":61,"local":"18:00","low":53,"mid":81,"precip":0.0,"rh":97,"temp":-1.0,"time":"2026-02-06T16:00Z","wind":6.1},{"cloud":100,"dark":false,"high":100,"local":"19:00","low":62,"mid":97,"precip":0.0,"rh":98,"temp":-1.8,"time":"2026-02-06T17:00Z","wind":5.0},{"cloud":100,"dark":true,"high":100,"local":"20:00","low":63,"mid":99,"precip":0.0,"rh":100,"temp":-1.0,"time":"2026-02-06T18:00Z","wind":7.5},{"cloud":100,"dark":true,"high":100,"local":"21:00","low":46,"mid":99,"precip":0.0,"rh":100,"temp":-1.5,"time":"2026-02-06T19:00Z","wind":7.2},{"cloud":95,"dark":true,"high":16,"local":"22:00","low":94,"mid":15,"precip":0.0,"rh":100,"temp":-1.5,"time":"2026-02-06T20:00Z","wind":7.7},{"cloud":100,"dark":true,"high":0,"local":"23:00","low":100,"mid":0,"precip":0.0,"rh":96,"temp":-0.5,"time":"2026-02-06T21:00Z","wind":11.0},{"cloud":81,"dark":true,"high":13,"local":"00:00","low":78,"mid":8,"precip":0.0,"rh":99,"temp":-1.1,"time":"2026-02-06T22:00Z","wind":9.1},{"cloud":84,"dark":true,"high":5,"local":"01:00","low":83,"mid":10,"precip":0.0,"rh":100,"temp":-1.4,"time":"2026-02-06T23:00Z","wind":8.4},{"cloud":86,"dark":true,"high":0,"local":"02:00","low":84,"mid":12,"precip":0.0,"rh":99,"temp":-0.5,"time":"2026-02-07T00:00Z","wind":9.0},{"cloud":100,"dark":true,"high":0,"local":"03:00","low":100,"mid":0,"precip":0.0,"rh":99,"temp":-1.0,"time":"2026-02-07T01:00Z","wind":5.8},{"cloud":100,"dark":true,"high":0,"local":"04:00","low":100,"mid":0,"precip":0.0,"rh":100,"temp":-1.7,"time":"2026-02-07T02:00Z","wind":5.6},{"cloud":100,"dark":true,"high":0,"local":"05:00","low":100,"mid":0,"precip":0.0,"rh":100,"temp":-2.3,"time":"2026-02-07T03:00Z","wind":4.9},{"cloud":97,"dark":false,"high":0,"local":"06:00","low":97,"mid":0,"precip":0.0,"rh":99,"temp":-3.5,"time":"2026-02-07T04:00Z","wind":4.0},{"cloud":98,"dark":false,"high":0,"local":"07:00","low":97,"mid":7,"precip":0.0,"rh":98,"temp":-3.9,"time":"2026-02-07T05:00Z","wind":4.0},{"cloud":98,"dark":false,"high":0,"local":"08:00","low":98,"mid":4,"precip":0.0,"rh":100,"temp":-2.4,"time":"2026-02-07T06:00Z","wind":5.4}],"forecast_source":"history","forecast_updated_at":"2026-10-17T08:58:58Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-02-06T17:17:17Z","dark_hours":10.59,"dark_to":"2026-02-07T03:52:28Z","moon":{"illumination":0.74,"phase":"waning gibbous","waxing":false},"moon_free_dark_hours":3.7,"moonrise":"2026-02-06T21:00:15Z","moonset":"2026-02-07T07:42:15Z","sunrise":"2026-02-07T05:26:47Z","sunset":"2026-02-06T15:42:45Z","twilight":{"astronomical":{"end":"2026-02-06T17:17:17Z","start":"2026-02-07T03:52:28Z"},"civil":{"end":"2026-02-06T16:11:51Z","start":"2026-02-07T04:57:46Z"},"nautical":{"end":"2026-02-06T16:44:50Z","start":"2026-02-07T04:24:52Z"}},"window_end":"2026-02-07T10:00:00Z","window_start":"2026-02-06T10:00:00Z"},"night_date":"2026-02-06","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}