I’d like one that I can add external wireless sensors for stuff like temp, rainfall, windspeed etc. And have it display historical data to view trends. Also one that can be linked to the web somehow (if it’s got software that needs to run on a pc then must be compatible with a mac.)

Any suggestions?

I dunno, but someone here probably will:

http://theweatheroutlook.com/twocommunity/default.aspx?g=topics&f=2

quite low tech, but it works.

Will the stone interface with my PC?

Thanks for the web site, shall check it out.

bruneep stone gone could also be because of this chap 😉

My Dad uses an Oregon Scientific weather station which wirelessly logs rain, wind, pressure, temp, humidity etc. it has its own interface and also logs the data onto his computer.
He seems pretty happy with it, and built his own Stevenson screen as well as spending ages getting it running on a Linux box. He has had it ages now so I imagine software support is much improved now.

If you’re wanting to log the data to Wunderground something like this is a good buy. maplins do regular 50% of deals

Not sure about Mac compatability though. Try asking on Wunderground.com