What sensor should I use for for measuring temperature inside a concrete wall

[timjohnarm]

I'd like to get the temperature at various depths inside a 200mm concrete wall that is being used for thermal mass.
Sensor should have an accuracy of +/- 0.5C

Let's say 5 sensors one on the exterior of the wall, then at 50mm, 100mm, 150mm and the inside of the wall.

That way I can measure the heating effect as it passes through the wall.

I'd like to use the minimum number of wires possible so 1-wire, I2C or SPI seem to be the go. Not sure about 1-wire and multiple sensors.

I only want the temperature although humidity might be of interest.

Is the BME280 a good choice or is it overkill.

[MicroController]

Temperature range? Experiment or permanent installation, accessibility?

Not sure about 1-wire and multiple sensors.

Not a problem at all.

[BrianP]

I know you want minimum wire count but I have had great success using simple thermistors. They are cheap, available in hermetically sealed stainless steel packages and really easy to use. You can even run long wires to them - not something which is true of most digital sensors.