{"assessment":{"best_window":null,"cost":{"altitude":0.0,"clouds":5.05,"darkness":2.62,"moon":6.5},"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 13.1 of 13.1 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Not tonight","hourly":[{"alt":null,"cloud":100,"high":100,"iso":"2026-01-29T16:00Z","label":"unusable","low":100,"mid":100,"moon_alt":46,"precip":0.7,"q":0.0,"rh":100,"sky":"civil twilight","temp":-1.0,"time":"18:00","wind":2.7},{"alt":null,"cloud":100,"high":98,"iso":"2026-01-29T17:00Z","label":"unusable","low":100,"mid":98,"moon_alt":56,"precip":0.2,"q":0.0,"rh":100,"sky":"astronomical twilight","temp":-1.0,"time":"19:00","wind":3.7},{"alt":null,"cloud":100,"high":98,"iso":"2026-01-29T18:00Z","label":"unusable","low":100,"mid":98,"moon_alt":67,"precip":0.3,"q":0.0,"rh":100,"sky":"night","temp":-0.9,"time":"20:00","wind":3.5},{"alt":null,"cloud":100,"high":100,"iso":"2026-01-29T19:00Z","label":"unusable","low":100,"mid":97,"moon_alt":75,"precip":0.2,"q":0.0,"rh":99,"sky":"night","temp":-1.2,"time":"21:00","wind":3.6},{"alt":null,"cloud":100,"high":100,"iso":"2026-01-29T20:00Z","label":"unusable","low":100,"mid":99,"moon_alt":76,"precip":0.1,"q":0.0,"rh":99,"sky":"night","temp":-1.0,"time":"22:00","wind":6.7},{"alt":null,"cloud":100,"high":84,"iso":"2026-01-29T21:00Z","label":"unusable","low":100,"mid":100,"moon_alt":69,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":-1.1,"time":"23:00","wind":6.7},{"alt":null,"cloud":100,"high":89,"iso":"2026-01-29T22:00Z","label":"unusable","low":100,"mid":98,"moon_alt":59,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":-1.0,"time":"00:00","wind":6.4},{"alt":null,"cloud":100,"high":100,"iso":"2026-01-29T23:00Z","label":"unusable","low":100,"mid":100,"moon_alt":48,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":-1.1,"time":"01:00","wind":5.9},{"alt":null,"cloud":100,"high":99,"iso":"2026-01-30T00:00Z","label":"unusable","low":100,"mid":100,"moon_alt":37,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":-1.2,"time":"02:00","wind":5.8},{"alt":null,"cloud":100,"high":99,"iso":"2026-01-30T01:00Z","label":"unusable","low":100,"mid":100,"moon_alt":26,"precip":0.2,"q":0.0,"rh":100,"sky":"night","temp":-1.4,"time":"03:00","wind":5.3},{"alt":null,"cloud":100,"high":99,"iso":"2026-01-30T02:00Z","label":"unusable","low":100,"mid":100,"moon_alt":16,"precip":0.5,"q":0.0,"rh":100,"sky":"night","temp":-1.5,"time":"04:00","wind":7.1},{"alt":null,"cloud":100,"high":66,"iso":"2026-01-30T03:00Z","label":"unusable","low":100,"mid":100,"moon_alt":7,"precip":0.5,"q":0.0,"rh":99,"sky":"night","temp":-1.6,"time":"05:00","wind":7.7},{"alt":null,"cloud":100,"high":36,"iso":"2026-01-30T04:00Z","label":"unusable","low":98,"mid":100,"moon_alt":-2,"precip":0.3,"q":0.0,"rh":99,"sky":"astronomical twilight","temp":-1.7,"time":"06:00","wind":8.9},{"alt":null,"cloud":100,"high":42,"iso":"2026-01-30T05:00Z","label":"unusable","low":100,"mid":100,"moon_alt":-10,"precip":0.1,"q":0.0,"rh":98,"sky":"nautical twilight","temp":-1.9,"time":"07:00","wind":8.7}],"peak_quality":0.0,"peak_sky":1.0,"quality_hours":0.0,"reasons":["moonlight cost 6.5 quality-hours","cloud cover cost 5.1 quality-hours","daylight and twilight cost 2.6 quality-hours"],"reference_hours":4.0,"score":0,"score_astronomy":100,"score_weather":0,"sky_hours":5.05,"verdict":"unusable","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-01-30T05:40Z","end_local":"07:40","hours":14.17,"label":"unusable","mean_quality":0.0,"start":"2026-01-29T15:30Z","start_local":"17:30"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":100,"dark":false,"high":100,"local":"17:00","low":100,"mid":98,"precip":2.7,"rh":99,"temp":-0.6,"time":"2026-01-29T15:00Z","wind":0.8},{"cloud":100,"dark":false,"high":100,"local":"18:00","low":100,"mid":100,"precip":0.7,"rh":100,"temp":-1.0,"time":"2026-01-29T16:00Z","wind":2.7},{"cloud":100,"dark":false,"high":98,"local":"19:00","low":100,"mid":98,"precip":0.2,"rh":100,"temp":-1.0,"time":"2026-01-29T17:00Z","wind":3.7},{"cloud":100,"dark":true,"high":98,"local":"20:00","low":100,"mid":98,"precip":0.3,"rh":100,"temp":-0.9,"time":"2026-01-29T18:00Z","wind":3.5},{"cloud":100,"dark":true,"high":100,"local":"21:00","low":100,"mid":97,"precip":0.2,"rh":99,"temp":-1.2,"time":"2026-01-29T19:00Z","wind":3.6},{"cloud":100,"dark":true,"high":100,"local":"22:00","low":100,"mid":99,"precip":0.1,"rh":99,"temp":-1.0,"time":"2026-01-29T20:00Z","wind":6.7},{"cloud":100,"dark":true,"high":84,"local":"23:00","low":100,"mid":100,"precip":0.0,"rh":99,"temp":-1.1,"time":"2026-01-29T21:00Z","wind":6.7},{"cloud":100,"dark":true,"high":89,"local":"00:00","low":100,"mid":98,"precip":0.0,"rh":99,"temp":-1.0,"time":"2026-01-29T22:00Z","wind":6.4},{"cloud":100,"dark":true,"high":100,"local":"01:00","low":100,"mid":100,"precip":0.0,"rh":99,"temp":-1.1,"time":"2026-01-29T23:00Z","wind":5.9},{"cloud":100,"dark":true,"high":99,"local":"02:00","low":100,"mid":100,"precip":0.0,"rh":99,"temp":-1.2,"time":"2026-01-30T00:00Z","wind":5.8},{"cloud":100,"dark":true,"high":99,"local":"03:00","low":100,"mid":100,"precip":0.2,"rh":100,"temp":-1.4,"time":"2026-01-30T01:00Z","wind":5.3},{"cloud":100,"dark":true,"high":99,"local":"04:00","low":100,"mid":100,"precip":0.5,"rh":100,"temp":-1.5,"time":"2026-01-30T02:00Z","wind":7.1},{"cloud":100,"dark":true,"high":66,"local":"05:00","low":100,"mid":100,"precip":0.5,"rh":99,"temp":-1.6,"time":"2026-01-30T03:00Z","wind":7.7},{"cloud":100,"dark":false,"high":36,"local":"06:00","low":98,"mid":100,"precip":0.3,"rh":99,"temp":-1.7,"time":"2026-01-30T04:00Z","wind":8.9},{"cloud":100,"dark":false,"high":42,"local":"07:00","low":100,"mid":100,"precip":0.1,"rh":98,"temp":-1.9,"time":"2026-01-30T05:00Z","wind":8.7},{"cloud":100,"dark":false,"high":0,"local":"08:00","low":100,"mid":80,"precip":0.0,"rh":99,"temp":-1.7,"time":"2026-01-30T06:00Z","wind":8.9}],"forecast_source":"history","forecast_updated_at":"2026-10-17T12:13:03Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-01-29T17:08:24Z","dark_hours":10.85,"dark_to":"2026-01-30T03:59:37Z","moon":{"illumination":0.882,"phase":"waxing gibbous","waxing":true},"moon_free_dark_hours":0.23,"moonrise":"2026-01-29T11:28:27Z","moonset":"2026-01-30T03:44:11Z","sunrise":"2026-01-30T05:35:15Z","sunset":"2026-01-29T15:32:32Z","twilight":{"astronomical":{"end":"2026-01-29T17:08:24Z","start":"2026-01-30T03:59:37Z"},"civil":{"end":"2026-01-29T16:02:12Z","start":"2026-01-30T05:05:40Z"},"nautical":{"end":"2026-01-29T16:35:40Z","start":"2026-01-30T04:32:18Z"}},"window_end":"2026-01-30T10:00:00Z","window_start":"2026-01-29T10:00:00Z"},"night_date":"2026-01-29","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
