set term pngc enh font "IPAGothic,10" size 480,360
set out "axes_y1y2.png"
set xlabel "月" font ",12"
set ylabel "気温"  font ",12" tc rgb "dark-red"
set y2label "降水量" font ",12" tc rgb "navy"
set ytics nomirror
set y2tics nomirror
set boxwidth 0.8
set xtics 1,1,12
set yrange [0:30]
set y2range [0:300]
plot \
"tokyo.dat" u 1:3  axis x1y2 w boxes fill transparent solid 0.5  \
   lc rgb "navy" t "降水量", \
"" u 1:4  w l lw 2 lc rgb "dark-red" t "気温" 

#
# "tokyo.dat"：東京の過去の平均気象情報
#
# # 気象庁 > 気象統計情報：http://www.jma.go.jp/jma/menu/report.html
# #月 気圧   降水  気温 蒸気圧 相対湿度
# 1  1011.4  52.3   6.1	  4.6	49	
# 2  1011.2  56.1   6.5	  4.9	50	
# 3  1011.0  117.5  9.4	  6.6	55	
# 4  1009.9  124.5  14.6  10.0	60	
# 5  1007.7  137.8  18.9  14.1	65	
# 6  1005.1  167.7  22.1  19.0	72	
# 7  1004.5  153.5  25.8  24.2	73	
# 8  1005.9  168.2  27.4  25.8	71	
# 9  1008.7  209.9  23.8  21.0	71	
# 10 1012.2  197.8  18.5  14.1	66	
# 11 1013.7  92.5   13.3  9.3	59	
# 12 1012.5  51.0   8.7	  5.9	52