| Aggregation type | 
        Meaning | 
    
    
        | avg | 
        The average value in the aggregation period. | 
    
    
        | avg_ge(val) | 
        The number of days when the average value is greater than or equal to val. Aggregation
            period must be one day or longer. The argument val is a
            ValueTuple.
         | 
    
    
        | avg_le(val) | 
        The number of days when the average value is less than or equal to val. Aggregation period
            must be one day or longer. The argument val is a
            ValueTuple.
         | 
    
    
        | count | 
        The number of non-null values in the aggregation period.
         | 
    
    
        | diff | 
        The difference between the last and first value in the aggregation period.
         | 
    
    
        | exists | 
        Returns True if the observation type exists in the database. | 
    
    
        | first | 
        The first non-null value in the aggregation period. | 
    
    
        | firsttime | 
        The time of the first non-null value in the aggregation period.
         | 
    
    
        | gustdir | 
        The direction of the max gust in the aggregation period.
         | 
    
    
        | has_data | 
        Returns True if the observation type 
            exists (either in the database or as an xtype) and has at least one
            non-null value in the aggregation period.
         | 
    
    
        | last | 
        The last non-null value in the aggregation period. | 
    
    
        | lasttime | 
        The time of the last non-null value in the aggregation period.
         | 
    
    
        | max | 
        The maximum value in the aggregation period. | 
    
    
        | maxmin | 
        The maximum daily minimum in the aggregation period. Aggregation period must be one day or longer.
         | 
    
    
        | maxmintime | 
        The time of the maximum daily minimum. | 
    
    
        | maxsum | 
        The maximum daily sum in the aggregation period. Aggregation period must be one day or longer.
         | 
    
    
        | maxsumtime | 
        The time of the maximum daily sum. | 
    
    
        | maxtime | 
        The time of the maximum value. | 
    
    
        | max_ge(val) | 
        The number of days when the maximum value is greater than or equal to val. Aggregation
            period must be one day or longer. The argument val is a
            ValueTuple.
         | 
    
    
        | max_le(val) | 
        The number of days when the maximum value is less than or equal to val. Aggregation period
            must be one day or longer. The argument val is a
            ValueTuple.
         | 
    
    
        | meanmax | 
        The average daily maximum in the aggregation period. Aggregation period must be one day or longer.
         | 
    
    
        | meanmin | 
        The average daily minimum in the aggregation period. Aggregation period must be one day or longer.
         | 
    
    
        | min | 
        The minimum value in the aggregation period. | 
    
    
        | minmax | 
        The minimum daily maximum in the aggregation period. Aggregation period must be one day or longer.
         | 
    
    
        | minmaxtime | 
        The time of the minimum daily maximum. | 
    
    
        | minsum | 
        The minimum daily sum in the aggregation period. Aggregation period must be one day or longer.
         | 
    
    
        | minsumtime | 
        The time of the minimum daily sum. | 
    
    
        | mintime | 
        The time of the minimum value. | 
    
    
        | min_ge(val) | 
        The number of days when the minimum value is greater than or equal to val. Aggregation
            period must be one day or longer. The argument val is a
            ValueTuple.
         | 
    
    
        | min_le(val) | 
        The number of days when the minimum value is less than or equal to val. Aggregation period
            must be one day or longer. The argument val is a
            ValueTuple.
         | 
    
    
        | not_null | 
        
            Returns truthy if any value over the aggregation period is non-null.
         | 
    
    
        | rms | 
        The root mean square value in the aggregation period.
         | 
    
    
        | sum | 
        The sum of values in the aggregation period. | 
    
    
        | sum_ge(val) | 
        The number of days when the sum of value is greater than or equal to val. Aggregation
            period must be one day or longer. The argument val is a
            ValueTuple.
         | 
    
    
        | sum_le(val) | 
        The number of days when the sum of value is less than or equal to val. Aggregation period
            must be one day or longer. The argument val is a
            ValueTuple.
         | 
    
    
        | tderiv | 
        
            The time derivative between the last and first value in the aggregation period. This is the
            difference in value divided by the difference in time.
         | 
    
    
        | vecavg | 
        The vector average speed in the aggregation period. | 
    
    
        | vecdir | 
        The vector averaged direction during the aggregation period.
         |