Designated the HDC1050, it is a 1.3µA ±3% accurate digital humidity sensor that includes a ±0.2C accurate thermometer.

That supply current it at 1sample/s and 11-bit resolution, which can be raised to 14-bit, and a sleep mode offers 100nA quiescent.

Output is over I2C interface and operation is 2.7-5.5V and -40 to 125 deg C for the temperature sensor and -20 to 60 deg C for the humidity sensor.
The sensor comes in a 3x3mm 6pin, and is available now from Mouser, as is the HDC1050EVM evaluation module which uses USB for control and data streaming via a PC.