Determining the daily temperature range

The daily temperature range, or diurnal temperature variation as it is called in meteorology, is not so big a deal on Earth. In desert areas on Earth or generally on different planets, the variation is greater. We will have a look at the daily temperature range for the data we downloaded in the previous example:

1. To analyze temperature ranges, we will need to import the NumPy package and the NumPy masked arrays:

   import numpy as np
   import sys
   import numpy.ma as ma
   from datetime import datetime as dt

2. We will load a bit more data than that loaded in the previous section: dates of measurements in the YYYYMMDD format and the average daily temperature. Dates require special conversion. Firstly date strings are converted to dates and then to numbers as follows:

   to_float = lambda x: float(x.strip() or np.nan)
   to_date = lambda x: dt.strptime(x, "%Y%m%d").toordinal()
    
   dates, avg_temp, min_temp, max_temp = np.loadtxt(sys.argv[1], delimiter=',', usecols=(1, 11, 12...