TMI-Orion can help you measure humidity and temperature simultaneously
with its specific data loggers from PicoVACQ and NanoVACQ families.
Temperature sensor is Pt1000. The capacitive humidity sensor exists in two
versions : 80°C and 140°C.
The humidity/temperature loggers are available in NanoVACQ (31 mm diameter)
and PicoVACQ (15 mm diameter) families.
Some of these products exist in Ex version.

According to the different models, they can measure humidity rates from
5% to 95% with 3% uncertainety, even 1% on demand.