    let dewPoint: Double?                       // optional. The dew point in degrees Fahrenheit.
    let humidity: Double?                       // optional. The relative humidity, between 0 and 1, inclusive.
    let moonPhase: Double?                      // optional, only on daily. The fractional part of the lunation number during the given day: a value of 0 corresponds to a new moon, 0.25 to a first quarter moon, 0.5 to a full moon, and 0.75 to a last quarter moon. (The ranges in between these represent waxing crescent, waxing gibbous, waning gibbous, and waning crescent moons, respectively.)
    let nearestStormBearing: Double?            // optional, only on currently. The approximate direction of the nearest storm in degrees, with true north at 0° and progressing clockwise. (If nearestStormDistance is zero, then this value will not be defined.)
    let nearestStormDistance: Double?           // optional, only on currently. The approximate distance to the nearest storm in miles. (A storm distance of 0 doesn’t necessarily refer to a storm at the requested location, but rather a storm in the vicinity of that location.)
    let ozone: Double?                          // optional. The columnar density of total atmospheric ozone at the given time in Dobson units.
    let precipAccumulation: Double?             // optional, only on hourly and daily. The amount of snowfall accumulation expected to occur, in inches. (If no snowfall is expected, this property will not be defined.)