hd1/zipcode2tz

def timezone():
    code = request.args['q'].decode('utf-8')
    logging.debug('Searching for {0}'.format(code))
    url = 'http://www.boutell.com/zipcodes/zipcode.zip'
    with tempfile.NamedTemporaryFile(prefix='usps', suffix='.zip') as out:
        content = requests.get(url).content
        out.write(content)
        with zipfile.ZipFile(out) as zipfp:
            zips = zipfp.read('zipcode.csv')
            codes = StringIO()
            codes.write(os.linesep.join([s for s in zips.splitlines() if s.strip()]))
            codes.seek(0)
            zipreader = csv.DictReader(codes, fieldnames = ["zip","city","state","latitude","longitude","timezone","dst"])
            for line in zipreader:
                logging.debug('examining postal code {0}'.format(line['zip']))
                if line['zip'] == code:
                    return Response(__lookuptimezone(line), mimetype='text/plain')

def __lookuptimezone(line):
    if line['timezone'].endswith('5') and line['dst'] == '1':
        return 'EST5EDT'
    elif line['timezone'].endswith('5') and line['dst'] == '0':
        return 'EST5'
    elif line['timezone'].endswith('6') and line['dst'] == '1':
        return 'CST6CDT'
    elif line['timezone'].endswith('6') and line['dst'] == '0':
        return 'CST6'
    elif line['timezone'].endswith('7') and line['dst'] == '1':
        return 'MST7MDT'
    elif line['timezone'].endswith('7') and line['dst'] == '0':
        return 'MST7'
    elif line['timezone'].endswith('8') and line['dst'] == '1':
        return 'PST8PDT'
    elif line['timezone'].endswith('8') and line['dst'] == '0':
        return 'PST8'
    raise Exception, 'Invalid zipcdoe {0}'.format(line)