用多项式拟合线绘制最高温度

Question

我正在从http://data.rcc-acis.org/StnData检索数据。效果很好，我可以使用matplotlib可视化数据。我正在努力为值绘制一条4多项式线。我的代码在下面列出。我正在使用Python 3.7。任何帮助是极大的赞赏。

import urllib
import datetime
import urllib.request
import ast
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
import scipy.interpolate as ntrpl 
import numpy as np
import matplotlib as mpl


# create a static day of the month
#dayofmonth = ('01-01')
dayofmonth = ('11-26')

# testing out a range of years
y = datetime.datetime.today().year
years = list(range(y-1,y-50, -1))

i = 0
dateList=[]
minTList=[]
maxTList=[]
for year in years:
    sdate = (str(year) + '-' + dayofmonth)
    #print(sdate)

    url = "http://data.rcc-acis.org/StnData"

    values = {
    "sid": "KGGW",
    "date": sdate,
    "elems": "maxt,mint",
    "meta": "name",
    "output": "json"
    }

    data = urllib.parse.urlencode(values).encode("utf-8")


    req = urllib.request.Request(url, data)
    response = urllib.request.urlopen(req)
    results = response.read()
    results = results.decode()
    results = ast.literal_eval(results)

    if i < 1:
        n_label = results['meta']['name']
        i = 2
    for x in results["data"]:
            date,maxT,minT = x
            #setting the string of date to datetime

            date = date[0:4]
            date_obj = datetime.datetime.strptime(date,'%Y')
            dateList.append(date_obj)
            minTList.append(minT)
            maxTList.append(maxT)

minT_int = list(map(int,minTList))
maxT_int = list(map(int,maxTList))
n_label = n_label + " " + dayofmonth
#p1 = np.polyfit(newDates,h_temps,3)
def plot_graph(dates,h_temps,l_temps,label):
    #converting the dates into a readable format for pyplot
    newDates = mdates.date2num(dates)
    plt.gca().xaxis.set_major_formatter(mdates.DateFormatter('%Y'))
    plt.title(label)
    plt.gcf().autofmt_xdate()
    plt.plot(newDates,l_temps)
    plt.plot(newDates,h_temps)
    #p1 = np.polyfit(x,y,3)
    p1 = np.polyfit(newDates,h_temps,3)
    print(p1)
    plt.plot(newDates,p1)
    plt.show()
#print   
plot_graph(dateList,maxT_int,minT_int,n_label)