{"assessment":{"best_window":null,"cost":{"altitude":0.0,"clouds":11.88,"darkness":2.62,"moon":0.0},"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 13.4 of 13.4 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Not tonight","hourly":[{"alt":null,"cloud":100,"high":0,"iso":"2026-01-18T16:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-12,"precip":0.0,"q":0.0,"rh":85,"sky":"nautical twilight","temp":-10.6,"time":"18:00","wind":8.9},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-18T17:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-22,"precip":0.0,"q":0.0,"rh":89,"sky":"night","temp":-11.4,"time":"19:00","wind":8.8},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-18T18:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-33,"precip":0.0,"q":0.0,"rh":92,"sky":"night","temp":-11.6,"time":"20:00","wind":8.6},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-18T19:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-43,"precip":0.0,"q":0.0,"rh":92,"sky":"night","temp":-11.7,"time":"21:00","wind":9.0},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-18T20:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-54,"precip":0.0,"q":0.0,"rh":89,"sky":"night","temp":-11.6,"time":"22:00","wind":9.7},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-18T21:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-63,"precip":0.0,"q":0.0,"rh":88,"sky":"night","temp":-11.8,"time":"23:00","wind":9.4},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-18T22:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-70,"precip":0.0,"q":0.0,"rh":85,"sky":"night","temp":-11.7,"time":"00:00","wind":9.1},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-18T23:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-71,"precip":0.0,"q":0.0,"rh":87,"sky":"night","temp":-11.6,"time":"01:00","wind":9.1},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-19T00:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-66,"precip":0.0,"q":0.0,"rh":89,"sky":"night","temp":-12.0,"time":"02:00","wind":10.0},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-19T01:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-57,"precip":0.0,"q":0.0,"rh":88,"sky":"night","temp":-12.0,"time":"03:00","wind":9.1},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-19T02:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-46,"precip":0.0,"q":0.0,"rh":88,"sky":"night","temp":-12.1,"time":"04:00","wind":8.5},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-19T03:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-36,"precip":0.0,"q":0.0,"rh":86,"sky":"night","temp":-12.1,"time":"05:00","wind":8.1},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-19T04:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-25,"precip":0.0,"q":0.0,"rh":85,"sky":"night","temp":-12.3,"time":"06:00","wind":8.1},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-19T05:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-14,"precip":0.0,"q":0.0,"rh":84,"sky":"nautical twilight","temp":-12.4,"time":"07:00","wind":8.3}],"peak_quality":0.0,"peak_sky":1.0,"quality_hours":0.0,"reasons":["cloud cover cost 11.9 quality-hours","daylight and twilight cost 2.6 quality-hours"],"reference_hours":4.0,"score":0,"score_astronomy":100,"score_weather":0,"sky_hours":11.88,"verdict":"unusable","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-01-19T05:45Z","end_local":"07:45","hours":14.5,"label":"unusable","mean_quality":0.0,"start":"2026-01-18T15:15Z","start_local":"17:15"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":100,"dark":false,"high":0,"local":"17:00","low":100,"mid":0,"precip":0.0,"rh":79,"temp":-9.5,"time":"2026-01-18T15:00Z","wind":8.9},{"cloud":100,"dark":false,"high":0,"local":"18:00","low":100,"mid":0,"precip":0.0,"rh":85,"temp":-10.6,"time":"2026-01-18T16:00Z","wind":8.9},{"cloud":100,"dark":true,"high":0,"local":"19:00","low":100,"mid":0,"precip":0.0,"rh":89,"temp":-11.4,"time":"2026-01-18T17:00Z","wind":8.8},{"cloud":100,"dark":true,"high":0,"local":"20:00","low":100,"mid":0,"precip":0.0,"rh":92,"temp":-11.6,"time":"2026-01-18T18:00Z","wind":8.6},{"cloud":100,"dark":true,"high":0,"local":"21:00","low":100,"mid":0,"precip":0.0,"rh":92,"temp":-11.7,"time":"2026-01-18T19:00Z","wind":9.0},{"cloud":100,"dark":true,"high":0,"local":"22:00","low":100,"mid":0,"precip":0.0,"rh":89,"temp":-11.6,"time":"2026-01-18T20:00Z","wind":9.7},{"cloud":100,"dark":true,"high":0,"local":"23:00","low":100,"mid":0,"precip":0.0,"rh":88,"temp":-11.8,"time":"2026-01-18T21:00Z","wind":9.4},{"cloud":100,"dark":true,"high":0,"local":"00:00","low":100,"mid":0,"precip":0.0,"rh":85,"temp":-11.7,"time":"2026-01-18T22:00Z","wind":9.1},{"cloud":100,"dark":true,"high":0,"local":"01:00","low":100,"mid":0,"precip":0.0,"rh":87,"temp":-11.6,"time":"2026-01-18T23:00Z","wind":9.1},{"cloud":100,"dark":true,"high":0,"local":"02:00","low":100,"mid":0,"precip":0.0,"rh":89,"temp":-12.0,"time":"2026-01-19T00:00Z","wind":10.0},{"cloud":100,"dark":true,"high":0,"local":"03:00","low":100,"mid":0,"precip":0.0,"rh":88,"temp":-12.0,"time":"2026-01-19T01:00Z","wind":9.1},{"cloud":100,"dark":true,"high":0,"local":"04:00","low":100,"mid":0,"precip":0.0,"rh":88,"temp":-12.1,"time":"2026-01-19T02:00Z","wind":8.5},{"cloud":100,"dark":true,"high":0,"local":"05:00","low":100,"mid":0,"precip":0.0,"rh":86,"temp":-12.1,"time":"2026-01-19T03:00Z","wind":8.1},{"cloud":100,"dark":true,"high":0,"local":"06:00","low":100,"mid":0,"precip":0.0,"rh":85,"temp":-12.3,"time":"2026-01-19T04:00Z","wind":8.1},{"cloud":100,"dark":false,"high":0,"local":"07:00","low":100,"mid":0,"precip":0.0,"rh":84,"temp":-12.4,"time":"2026-01-19T05:00Z","wind":8.3},{"cloud":100,"dark":false,"high":0,"local":"08:00","low":100,"mid":0,"precip":0.0,"rh":83,"temp":-12.4,"time":"2026-01-19T06:00Z","wind":8.8}],"forecast_source":"history","forecast_updated_at":"2026-10-17T10:38:15Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-01-18T16:56:42Z","dark_hours":11.16,"dark_to":"2026-01-19T04:06:08Z","moon":{"illumination":0.001,"phase":"new moon","waxing":true},"moon_free_dark_hours":11.15,"moonrise":"2026-01-19T06:27:12Z","moonset":"2026-01-18T14:41:36Z","sunrise":"2026-01-19T05:43:44Z","sunset":"2026-01-18T15:18:55Z","twilight":{"astronomical":{"end":"2026-01-18T16:56:42Z","start":"2026-01-19T04:06:08Z"},"civil":{"end":"2026-01-18T15:49:23Z","start":"2026-01-19T05:13:20Z"},"nautical":{"end":"2026-01-18T16:23:31Z","start":"2026-01-19T04:39:16Z"}},"window_end":"2026-01-19T10:00:00Z","window_start":"2026-01-18T10:00:00Z"},"night_date":"2026-01-18","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
