RuuviTag as a Weather Station

Is it possible to leave it to measure data for a mont and then read history to phone?

Is there wifi-ruuvi on the way?

Not right now, we do have some proof-of-concepts of logging but nothing ready to use yet.

No, WiFi consumes too much power for a coin cell powered tag. You might be interested in Ruuvi Dongle project which collects Ruuvi data and sends it to cloud via WiFi.