Oklahoma Mesonet Pandas DataFrame

ok_mesonet.py

#!/Users//anaconda/bin/python
"""
  Python main module requires the correct python path.(see above).
    Args  sites startdate enddate
      sites: string - comma sperated sites
      startdate: YYY-MM-DD
      enddate: YYYY-MM-DD
    example:
      Single site:
        ./ok_mesonet.py adax 2014-01-01 2014-02-01
      Multiple Sites:
        ./ok_mesonet.py adax,nrmn 2014-01-01 2014-02-01
"""
import pandas as pd
from urllib2 import urlopen
from datetime import datetime,timedelta
import numpy as np
import sys

def get_station_data(sites,start_date,end_date):
  """
    returns a pandas dataFrame
    sites: list of sites
    start_date: date
    end_date: date
  """
  url_template ="https://www.mesonet.org/index.php/dataMdfMts/dataController/getFile/%d%02d%02d%s/mts/TEXT/"
  r = (end_date+timedelta(days=1)-start_date).days
  dates = [start_date+timedelta(days=i) for i in range(r)]
  pieces=[]
  for site in sites:
      for day in dates:
          url = url_template % (day.year,day.month,day.day,site)
          page = urlopen(url)
          df = pd.read_fwf(page,header=2,widths=[5,6,6,7,7,7,7,6,7,7,7,8,9,6,7,7,7,7,7,7,7,8,8,8],na_values=['-999','-998','-996','-995','-997'],skipfooter=1)
          df['DATE'] = datetime(day.year,day.month,day.day)
          pieces.append(df)
  return pd.concat(pieces)

def celcius2Fahrenheit(num):
  """ Returns Fahrenheit from Celcius"""
  return (num * 9/5) + 32

if __name__ == "__main__":
    pd.options.display.max_columns = 30
    pd.options.display.max_rows = 5000
    site=sys.argv[1].split(',')
    try:
        start_date=datetime.strptime(sys.argv[2],"%Y-%m-%d").date()
        end_date =datetime.strptime(sys.argv[3],"%Y-%m-%d").date()
    except:
        raise("Second and third argument must be date format YYYY-MM-DD")
    df =get_station_data(site,start_date,end_date)
    print "AIR Temperature Celcius - UTC Time"
    grouped = df.groupby(['STID',"DATE"])
    print grouped['TAIR'].agg([np.min, np.mean, np.max,np.size])