Good afternoon Parallaxians!
I've started writing a driver for this combination Temperature/Rel. Humidity sensor (only the I2C variant - there's also an analog variant, if I'm not mistaken):
The driver lives on github https://github.com/avsa242/sht3x-spin
It should work with SHT30, 31 and 35, although I only have a 31 to test it with.
It's still relatively early in development, although most everything is implemented. It uses one additional cog (for the PASM I2C driver - as always, many thanks to JonnyMac for this).
Included is a serial terminal-based demo that can be used to continually read the sensor data, as well as the serial number and status reg. All that might need to be changed are some constants at the top of the file for things like clock speed, pin assignments (this was developed on a PropBOE, so the "standard" I2C pins weren't used)