I'm doing something similar on my rpi3, but indoor. A few environment sensors + a basic thermostat script to control my box-fan-in-the-window-plus-smart-plug "HVAC" (not that its been anything interesting as far as control during the summer: ON). Data collection is mostly temp, CO2, and PM since I can somewhat calibrate those, plus pulling down the 24 forecasts from NOAA twice a day, all into a sqlite DB with grafana on top. I'm hoping to get some exterior sensors running as well, maybe off a zero or something smaller, but we'll see.

Bonus points, I can tinker with some probably over-complicated timeseries python classes for sqlite.