Reliability is my biggest issue.
My first unit was purchased in December of 2020. In June of 2021 I noticed its firmware was quite old compared to others. I emailed support and they said they needed to replace it as they identified an issue. It was producing readings that were within its operating limits. A few days later and some climbing I swapped it out. This was peak of brood X and I even had a cicada land on my arm and start singing which freaked me out. But a quick cell popped up and I heard thunder so I got wrapped up and was done. Or so I thought!
Next AM I noticed the UV was 0 and we had bright sun. Status showed UV failed. I opened a ticket and they remote rebooted and then most of the sensors were no longer working. They said the lightning from the storm yesterday may have fried it but I know from in the past having a tree not 30 feet from the tower getting bark peeled to the ground from a strike had no effect on my prior unit.
So a few days later, up and down the tower and Tempest number 3 is flying high. That one worked well up until the end of last September. The battery voltage was dropping fast after a few days of no sun. It would recover to 2.8 but as soon as the sun set it was back to 2.5V. Next few days of overcast it was down to 2.4 and then the report rate gets dropped to save power and it finally went offline. They replaced that with number 4 which (again) was put up.
On April 22, during a quick gusty shower, the barometric pressure showed a sudden drop of 5 inches of mercury! We were nowhere near any tornadoes for sure! Of course it's borked again, in the ticket they indicated they would sending out a replacement. This will be number five.
It's getting old fast and I do all climbing/rigging myself but make no mistake about it, I don't enjoy it!
This unit constantly reports rain events during most wind events over 15 mph. Of course towers and hardware are quite "chatty" when it comes to acoustics, which the rain sensor is based on. (It's a $.80 piezoelectric transducer found in most annoying beeper type alarms)
TEMPEST number SIX was installed on a roof tripod mast early May. One June 24 it went AWOL. I was out of town. When I returned I power cycled the outdoor unit and it did connect but its battery was very weak and was in slow mode. It did recover after a few days of full sun. I opened a ticket with WF support and they said it looks OK now that it has recharged.
On July 7th we had a gully washer thunderstorm. I noticed the barometric pressure was off again as before. Nearly six inches lower! I opened a ticket with WF. They told me they have a new and improved unit that will be arriving by the end of the month if I wanted to wait or they could send a replacement right away. I opted to wait. They claim the "new and improved" unit features fewer connection points inside and an insect screen to keep pests out of what I'm assuming is the temperature shield area. It's supposed to be here by the end of the month so we'll see. I'm done with putting it up on the tower!
I suppose I have too high of an expectation for an all in one solution coming in around $300 USD.
The only good thing I can say is their support is outstanding. The unit is past its 2 year warranty period and they pay for shipping both ways and haven't asked for a dime. They also help out in a timely manner with things like calibration issues, et al.
If this is something you put on a post by your garden, then no problem.
On a roof, better be prepared (and comfortable) using a ladder frequently!
You can see in my sig links to both TEMPEST and Ambient Weather 2000 systems. The AW is about $25 cheaper than the TEMPEST and produces decent results and has had zero issues since I put it up last November. It's on the same tower but much lower.
My biggest concern is with (presumably) 100s of thousands of these (TEMPEST) units reporting from all over the globe, a HUGE amount of data, what good is it if it's flawed! It's not just the rain that has accuracy issues. Wind at times is just plain wrong. I've had the anemometer showing a constant 20 mph breeze in fog whereas the other real instruments are showing 0.0. Flying insects like sweat bees and even lady bugs traveling in the sensor gap will wreak havoc with the wind often showing gusts of 30-40 mph on days where the real wind never exceeds 10 mph. The anemometer also seems to be extremely sensitive to flow that's slightly off axis. Other ultrasonics, particularly professional units (eg. Vaisala) have never had such issues. I know I'm comparing a Rolls Royce to a Pinto but you get the idea.