There are two interesting tutorials with WiFi ESP8266.
The first of them is WiFi repeater/extender and second tutorial is how to use DHT11 temperature/humidity sensor with NodeMCU (ESP12E).
The first tutorial, how to use make expander/repeater, is described in great detail.
Notice: The power of ESP8266 is not so good like single purpose device, so can’t expect high speed internet or something else.
It would be use like repeater for your WiFi temperature sensor.
http://runtimeprojects.com/2017/03/extend-wifi-with-an-esp8266/
The second tutorial is “how to get data from temperature/humidity sensor DHT11“.
In this tutorial is used NodeMCU development board for ESP8266 which uses ESP12E module.
Temperature and humidity you find on web browser in local network. NodeMCU creates webserver.
Another parts of tutorial are MQTT and Mosquitto a continue of MQTT.
