Wunderground API: Streamlined python 2.7 code using the requests package. Must register at http://www.wunderground.com/weather/api/ and insert your personal key.

wunderground_current.py

import requests
data = requests.get('http://api.wunderground.com/api/INSERT_KEY_HERE/geolookup/conditions/q/Switzerland/Zurich.json').json()
location = data['location']['city']
temp_c = data['current_observation']['temp_c']
print "Current temperature in %s is: %s C" % (location, temp_c)

wunderground_historical.py

import requests
def get_precip(gooddate):
    urlstart = 'http://api.wunderground.com/api/INSERT_KEY_HERE/history_'
    urlend = '/q/Switzerland/Zurich.json'

    url = urlstart + str(gooddate) + urlend
    data = requests.get(url).json()
    for summary in data['history']['dailysummary']:
        print ','.join((gooddate,summary['date']['year'],summary['date']['mon'],summary['date']['mday'],summary['precipm'], summary['maxtempm'], summary['meantempm'],summary['mintempm']))

if __name__ == "__main__":
    from datetime import date
    from dateutil.rrule import rrule, DAILY

    a = date(2013, 1, 1)
    b = date(2013, 12, 31)

    for dt in rrule(DAILY, dtstart=a, until=b):
        get_precip(dt.strftime("%Y%m%d"))

It's very useful,I have using your code to get data, can you tell me if I want to data for month wise, not day wise ,then what I have to changes in your code?
for example: I want data for month wise,
year , month, average_high_temp , average_low_temp, precipitation , humadity...
2015 Jan 25 20 0 10 likewise....
can you please help for this?