I am sure that this question has already been asked, but my searches just can’t find the posts. Is there any FUNCTIONAL difference between the original Weatherflow product and the current Tempest? How about any other reason to upgrade?
Peace,
Dr. Z.
Do you mean the original Sky and Air device which is no longer available?
If you have a Tempest then you have the latest model.
If you have a Sky and an Air then you could upgrade to a Tempest but in my opinion there is no advantage.
I can describe the differences but if you own a Sky and an Air most of the differences are obvious.
Basically the Tempest combines the features of a Sky and an Air into a single device. Which creates some benefits and some disadvantages. Like the thermometer can not be positioned in the shade if the wind sensor is above all surrounding obstructions. And the power supply looses the feature of inserting AA batteries.
Search this forum for ‘Sky’ and ‘Air’ to see the previous model.
Cheers Ian 
No. Not unless you require a one-sensor solution.
Personally I like Air+Sky since both can be run off batteries and can be optimally located for what each measures, although the Air is quite massive for what few measurements it actually provides. The support for batteries means the Sky can make it through any dark season just fine, at the cost of needing to occasionally swap in new AA’s. The downside is that you need to occasionally take the unit down to do so.
The benefit of the Tempest is running off solar ‘if’ it stays charged enough to last during the dark season where you are, but that depends on where you’re located and how you sited your unit. There are a number of downsides related how the Tempest case heats up and cools off and thereby affecting your temperature readings, but it does have the magic rain sensor coating to try to get more accurate rain readings (didn’t work for me, FWIW). So for some folks it’s fine. Others have a lesser experience.
If you’re happy with your Air+Sky save your money at this point I think…