Weather

7 tools: wind chill (apparent temperature with wind), heat index (feels-like with humidity), dew point, humidity (relative ↔ absolute), UV exposure time (by skin type), sunrise/sunset (from latitude + longitude), and moon phase + illumination.

Canadian/US standard formula (2001 update): WC = 13.12 + 0.6215T − 11.37·V^0.16 + 0.3965·T·V^0.16, where T is °C and V is wind speed in km/h. Valid for T ≤ 10°C and V ≥ 4.8 km/h.

Yes for warm-weather feels-like. Heat index uses temperature and relative humidity (Rothfusz / Steadman formula). Wind chill is used for cold weather. Both are 'apparent temperature' measures.

Astronomical algorithm with ~1 minute accuracy under standard atmospheric refraction. Type your latitude / longitude / date — output is in UTC (convert to your local zone separately, or use the Timezone calculator).

Synodic period of 29.530588853 days. The calculator outputs the named phase (New, First Quarter, Full, Last Quarter, etc.) and illumination %. Accurate enough for everyday use; for astronomy / astrology timing of within minutes, use a specialised ephemeris.

Depends on your skin type (Fitzpatrick I-VI) and the current UV index. The UV Exposure calculator multiplies base time by 6/UVI and divides by skin type to give an estimated time to first sunburn. Always wear SPF 30+; this is a minimum, not a recommendation.