{"assessment":{"best_window":null,"cost":{"altitude":0.0,"clouds":9.62,"darkness":2.46,"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 11.1 of 11.1 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Not tonight","hourly":[{"alt":null,"cloud":100,"high":100,"iso":"2026-03-17T17:00Z","label":"unusable","low":73,"mid":0,"moon_alt":-24,"precip":0.0,"q":0.0,"rh":88,"sky":"nautical twilight","temp":-3.4,"time":"19:00","wind":4.2},{"alt":null,"cloud":100,"high":100,"iso":"2026-03-17T18:00Z","label":"unusable","low":38,"mid":0,"moon_alt":-34,"precip":0.0,"q":0.0,"rh":93,"sky":"astronomical twilight","temp":-4.4,"time":"20:00","wind":4.0},{"alt":null,"cloud":100,"high":100,"iso":"2026-03-17T19:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-43,"precip":0.0,"q":0.0,"rh":93,"sky":"night","temp":-4.1,"time":"21:00","wind":8.5},{"alt":null,"cloud":100,"high":100,"iso":"2026-03-17T20:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-50,"precip":0.0,"q":0.0,"rh":94,"sky":"night","temp":-3.6,"time":"22:00","wind":9.6},{"alt":null,"cloud":100,"high":100,"iso":"2026-03-17T21:00Z","label":"unusable","low":94,"mid":29,"moon_alt":-55,"precip":0.0,"q":0.0,"rh":89,"sky":"night","temp":-3.9,"time":"23:00","wind":9.6},{"alt":null,"cloud":100,"high":100,"iso":"2026-03-17T22:00Z","label":"unusable","low":100,"mid":100,"moon_alt":-55,"precip":0.0,"q":0.0,"rh":91,"sky":"night","temp":-4.6,"time":"00:00","wind":7.8},{"alt":null,"cloud":100,"high":100,"iso":"2026-03-17T23:00Z","label":"unusable","low":100,"mid":100,"moon_alt":-51,"precip":0.0,"q":0.0,"rh":97,"sky":"night","temp":-5.1,"time":"01:00","wind":6.4},{"alt":null,"cloud":100,"high":100,"iso":"2026-03-18T00:00Z","label":"unusable","low":100,"mid":100,"moon_alt":-43,"precip":0.0,"q":0.0,"rh":96,"sky":"night","temp":-5.1,"time":"02:00","wind":6.7},{"alt":null,"cloud":100,"high":99,"iso":"2026-03-18T01:00Z","label":"unusable","low":100,"mid":100,"moon_alt":-34,"precip":0.0,"q":0.0,"rh":97,"sky":"night","temp":-5.0,"time":"03:00","wind":7.0},{"alt":null,"cloud":100,"high":100,"iso":"2026-03-18T02:00Z","label":"unusable","low":100,"mid":100,"moon_alt":-23,"precip":0.0,"q":0.0,"rh":97,"sky":"night","temp":-5.0,"time":"04:00","wind":6.9},{"alt":null,"cloud":100,"high":99,"iso":"2026-03-18T03:00Z","label":"unusable","low":100,"mid":100,"moon_alt":-13,"precip":0.1,"q":0.0,"rh":96,"sky":"astronomical twilight","temp":-5.0,"time":"05:00","wind":7.3},{"alt":null,"cloud":100,"high":100,"iso":"2026-03-18T04:00Z","label":"unusable","low":100,"mid":100,"moon_alt":-2,"precip":0.1,"q":0.0,"rh":92,"sky":"nautical twilight","temp":-4.9,"time":"06:00","wind":7.2}],"peak_quality":0.0,"peak_sky":1.0,"quality_hours":0.0,"reasons":["cloud cover cost 9.6 quality-hours","daylight and twilight cost 2.5 quality-hours"],"reference_hours":4.0,"score":0,"score_astronomy":100,"score_weather":0,"sky_hours":9.62,"verdict":"unusable","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-03-18T04:30Z","end_local":"06:30","hours":12.08,"label":"unusable","mean_quality":0.0,"start":"2026-03-17T16:25Z","start_local":"18:25"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":100,"dark":false,"high":100,"local":"18:00","low":100,"mid":0,"precip":0.0,"rh":76,"temp":-1.7,"time":"2026-03-17T16:00Z","wind":8.0},{"cloud":100,"dark":false,"high":100,"local":"19:00","low":73,"mid":0,"precip":0.0,"rh":88,"temp":-3.4,"time":"2026-03-17T17:00Z","wind":4.2},{"cloud":100,"dark":false,"high":100,"local":"20:00","low":38,"mid":0,"precip":0.0,"rh":93,"temp":-4.4,"time":"2026-03-17T18:00Z","wind":4.0},{"cloud":100,"dark":true,"high":100,"local":"21:00","low":100,"mid":0,"precip":0.0,"rh":93,"temp":-4.1,"time":"2026-03-17T19:00Z","wind":8.5},{"cloud":100,"dark":true,"high":100,"local":"22:00","low":100,"mid":0,"precip":0.0,"rh":94,"temp":-3.6,"time":"2026-03-17T20:00Z","wind":9.6},{"cloud":100,"dark":true,"high":100,"local":"23:00","low":94,"mid":29,"precip":0.0,"rh":89,"temp":-3.9,"time":"2026-03-17T21:00Z","wind":9.6},{"cloud":100,"dark":true,"high":100,"local":"00:00","low":100,"mid":100,"precip":0.0,"rh":91,"temp":-4.6,"time":"2026-03-17T22:00Z","wind":7.8},{"cloud":100,"dark":true,"high":100,"local":"01:00","low":100,"mid":100,"precip":0.0,"rh":97,"temp":-5.1,"time":"2026-03-17T23:00Z","wind":6.4},{"cloud":100,"dark":true,"high":100,"local":"02:00","low":100,"mid":100,"precip":0.0,"rh":96,"temp":-5.1,"time":"2026-03-18T00:00Z","wind":6.7},{"cloud":100,"dark":true,"high":99,"local":"03:00","low":100,"mid":100,"precip":0.0,"rh":97,"temp":-5.0,"time":"2026-03-18T01:00Z","wind":7.0},{"cloud":100,"dark":true,"high":100,"local":"04:00","low":100,"mid":100,"precip":0.0,"rh":97,"temp":-5.0,"time":"2026-03-18T02:00Z","wind":6.9},{"cloud":100,"dark":false,"high":99,"local":"05:00","low":100,"mid":100,"precip":0.1,"rh":96,"temp":-5.0,"time":"2026-03-18T03:00Z","wind":7.3},{"cloud":100,"dark":false,"high":100,"local":"06:00","low":100,"mid":100,"precip":0.1,"rh":92,"temp":-4.9,"time":"2026-03-18T04:00Z","wind":7.2},{"cloud":100,"dark":false,"high":69,"local":"07:00","low":100,"mid":100,"precip":0.0,"rh":92,"temp":-4.9,"time":"2026-03-18T05:00Z","wind":7.8}],"forecast_source":"history","forecast_updated_at":"2026-10-15T22:43:49Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-03-17T18:02:42Z","dark_hours":8.88,"dark_to":"2026-03-18T02:55:14Z","moon":{"illumination":0.016,"phase":"new moon","waxing":false},"moon_free_dark_hours":8.87,"moonrise":"2026-03-18T04:09:17Z","moonset":"2026-03-17T14:45:23Z","sunrise":"2026-03-18T04:28:08Z","sunset":"2026-03-17T16:29:40Z","twilight":{"astronomical":{"end":"2026-03-17T18:02:42Z","start":"2026-03-18T02:55:14Z"},"civil":{"end":"2026-03-17T16:57:23Z","start":"2026-03-18T04:00:28Z"},"nautical":{"end":"2026-03-17T17:29:46Z","start":"2026-03-18T03:28:07Z"}},"window_end":"2026-03-18T10:00:00Z","window_start":"2026-03-17T10:00:00Z"},"night_date":"2026-03-17","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
