min_t = t_mean - t_spread
max_t = t_mean + t_spread
-plot "/dev/shm/DS18B20-temperature" using ($1+7200):($2 > min_t && $2 < max_t ? $2 : '') with dots title "DS18B20 deg. C","/dev/shm/DHT22-temperature" using ($1+7200):($2 > min_t && $2 < max_t ? $2 : '') with dots title "DHT22 deg. C"
+plot "/dev/shm/DS18B20-temperature" using ($1+7200):($2 > min_t && $2 < max_t ? $2 : '') with dots title "DS18B20 deg. C" \
+,"/dev/shm/DHT22-temperature" using ($1+7200):($2 > min_t && $2 < max_t ? $2 : '') with dots title "DHT22 deg. C" \
+,"/dev/shm/rtl_433-temperature" using ($1+7200):($2 > min_t && $2 < max_t ? $2 : '') with dots title "RTL 433 deg. C"
set origin 0.0, 0.0