forecastFrequency 
  The frequency of predictions in a forecast.
Valid intervals are an integer followed by Y (Year), M (Month), W (Week), D (Day), H (Hour), and min (Minute). For example, 1D indicates every day and 15min indicates every 15 minutes. The value of a frequency must not overlap with the next larger frequency. For example, you must use a frequency of 1H instead of 60min.
The valid values for each frequency are the following:
- Minute - 1-59 
- Hour - 1-23 
- Day - 1-6 
- Week - 1-4 
- Month - 1-11 
- Year - 1