import os
import sys
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.dates import DayLocator, HourLocator, DateFormatter, drange
import datetime as dt

ff = "temp-25c.txt"
fn = open(ff, "r")
tt = np.array([])
d1 = np.array([])
d2 = np.array([])
d3 = np.array([])
d4 = np.array([])
for i in fn.readlines()[4:]:
    i = i.split()
    j = [int(ii) for ii in i[0].split('-')]
    k = [int(ii) for ii in i[1].split(':')]
    a = dt.datetime(j[2], j[0], j[1], k[0], k[1], k[2])
    tt = np.append(tt, a)
    d1 = np.append(d1, int(i[4]))
    d2 = np.append(d2, int(i[4]))
    d3 = np.append(d3, int(i[4]))
    d4 = np.append(d4, int(i[4]))

ax = plt.subplot(111)
ax.plot_date(tt, d1)
ax.plot_date(tt, d2)
ax.plot_date(tt, d3)
ax.plot_date(tt, d4)
plt.setp( ax.xaxis.get_majorticklabels(), rotation=70, horizontalalignment='right' )
plt.tight_layout(
plt.savefig("res.png")
~