plot.conf

# Separator
set datafile separator ","

# Title
set title "DHT22 Inside the observatory"

# X-axis label
set xlabel "Date/Time\n"

# Title for Y-axis
#set ylabel "(*C)"
set yrange [-15:50]

# Title for Y2-axis
#set y2label "(%)"

# Place ticks on second Y2-axis
set y2tics border

# Automatic scaling
set autoscale

set grid

# Define that data on X-axis should be interpreted as time
set xdata time

# Time in log-file is given in format YYYY-MM-DD HH:MM:SS
set timefmt '%m/%d/%y,%H:%M'

# Display the last 7 days
set xrange [time(0) - 7*24*60*60:]

# Display notation for time
set format x "%d-%m\n%Y"

set key outside bottom center

# output into png file
set terminal png size 800,500
set output "plot.png"

# Below, "using 1:2" means use column 1 of the data for X, and column 2 of the data for Y

# read data from file and generate plot
plot "plot.txt" using 1:3 title "Temperature (*C)" with lines lw 2 lc rgb "red", "plot.txt" using 1:4 title "R. Humidity (%)" with lines lw 2 lc rgb "dark-green", "plot.txt" using 1:5 title "Dew point (*C)" with lines lw 2 lc rgb "blue",  "plot.txt" using 1:6 title "Heat index (*C)" with lines lw 2 lc rgb "brown"