from urllib.request import urlopen
import json
f = urlopen('http://api.wunderground.com/api/Your_Key/conditions/q/CA/San_Francisco.json')
json_string = f.read()
parsed_json = json.loads(json_string.decode('utf-8'))
temp_c = parsed_json['current_observation']['temp_c']
temp_f = parsed_json['current_observation']['temp_f']
print (temp_c, temp_f)
f.close()