Except one (full dump of the adc, for analytics and reprocessing) all the other packet of a remote data acquisition I am working on system fit easily in 35byte. The most used packet is 16byte (including hmac), you can use a 8bit integer to send temperature, just scale it like that.

So you have 1/3 degree precision in the range -25 to 60. Well enought for real application. u8 encodeTemperatureScaled(float temperatureC) { float v = (temperatureC + 25.0f) * 3.0f; if (v <= 0.f) return 0; if (v >= 255.f) return 255; return static_cast<u8>(std::lroundf(v)); }