Nice to read that there are already all kind of LoRa beehive monitors! I recently made one myself (for my sister, she has two beehives) as a learning project (my first pcb design and first LoRa project). Made a simple beacon with the RFM95 and an attiny85v on a coin cell:
Both the attiny85 and the RFM95 already have an internal temperature sensor (both with a resolution of 1 degree C). With some calibration and sub degree interpolation (by averaging multiple reads) a nice accuracy seems possible:
red = external DHT22 temperature sensor
purple = averaged temperature measurements from the beacon
Also designed a small 3D printed enclosure in an appropriate shape 
:
I expect the module to have a lifetime of around 3 years on a single CR2032 coin cell, measuring the temperature every hour and sending 4 hours of data at once 6 times a day (+ a 7th message with the coin cell voltage and some backup temperature data in case one of the messages isn’t received).
Was a fun project to work on 