How to interpret duplicate hourly records - Wunderground API

Question

For a specific historical query: http://api.wunderground.com/api/MY_API_KEY/history_20131231/geolookup/q/Beijing/Beijing.json

I get periodic, duplicate data for a given hour. For example, On January 1st, 2014 at 2:00 pm there will be two rows with distinct data, such as:

"Year", "Month", "Day", "Hour", "Min", "Humidity", "Temperature_F", "Windspeed_mph", "Wind_direction_deg", "Air_Pressure_mb"
"2014","01","01","14","00","7","53","6.7","250","1014"
"2014","01","01","14","00","13","51.8","17.9","300","1014"

I don't think it's a problem with my code, but rather the api. How do I explain this? Anyway, here is my code:

'''
Takes a date and file name, returns an hourly print out of historical weather
data, including humidity, temperature, wind speed, wind direction, and air      pressure
'''

def print_column_headings(headers, file_name):
    with open (file_name, 'wb') as initial_file:
        w = csv.writer(initial_file, quoting=csv.QUOTE_ALL)
        w.writerow(headers)
    initial_file.close()

def print_one_day_of_weather_data(year, month, day, max_rows, file_to_write):

# get data
url = 'http://api.wunderground.com/api/<MY_API_KEY>/history_' + year + month + day +'/geolookup/q/Beijing/Beijing.json'
f = urllib2.urlopen(url)
print url
json_string = f.read()
parsed_json = json.loads(json_string)

# paramterize data
all_obs = parsed_json['history']['observations']

# if we reach the end of the observations
for n in range(0, len(all_obs)):
    # or we exceed the max rows desired
    if n > max_rows:
        return 0
    else: 
        base_path = all_obs[n]
        date_path = base_path['date']
        year = date_path['year']
        month = date_path['mon']
        day = date_path['mday']
        hour = date_path['hour']
        min = date_path['min']
        humidity = base_path['hum']
        temp_f = base_path['tempi']
        windspeed_mph = base_path['wspdi']
        winddir_deg = base_path['wdird']
        air_pressure_mb = base_path['pressurem']

        # utc time
        params = [year, month, day, hour, min, humidity, temp_f, windspeed_mph, winddir_deg, air_pressure_mb]

        print params

        with open (file_to_write, 'a') as csvfile:
            w = csv.writer(csvfile, quoting=csv.QUOTE_ALL)
            w.writerow(params)

        csvfile.close()


headers = ("Year", "Month", "Day", "Hour", "Min", "Humidity", "Temperature_F", "Windspeed_mph", "Wind_direction_deg", "Air_Pressure_mb")

def append_leading_zeroes(num):
return "%02d" % (num,)

def days_in_a_month(year, month_num):
    return calendar.monthrange(year, month_num)[1]

def file_namer(city, month_num, year): 
    return "raw weather - local time " + city + "-" + calendar.month_name[month_num] + "-" + str(year) + ".csv"

def gen_entire_month(city, month, year, should_print_headers, start_at_day=1):
    file_name = file_namer(city, month, year)

    if should_print_headers:
      print_column_headings(headers, file_name)

  for day in range(start_at_day, days_in_a_month(year, month) + 1):
    print_one_day_of_weather_data(str(year), append_leading_zeroes(month), append_leading_zeroes(day), 100, file_name)      
    # if we make too many calls in a short period of time, the API refuses are calls
    time.sleep(60)

gen_entire_month("Beijing", 1, 2014, should_print_headers=True)

In the JSON response for Beijing, how many observation locations are listed? — John1024, Apr 12 '15 at 05:26
@John1024 I think 1, but here is a given day: https://jsonblob.com/552a0ab7e4b0857874700642. — compguy24, Apr 12 '15 at 06:03

score 0 · Answer 1 · answered Apr 13 '15 at 16:15

We get some obs from 2 NWS or World Meteorological Organization sources. Look in the field "metar" and only use readings that start with "METAR ..." because those are from the obs station. The ones that begin with anything else, like AAXX are special readings. They are also legit, but by blending the 2 sources, its confusing.

How to interpret duplicate hourly records - Wunderground API

1 Answers1