ProsWonderful interfaceEasy setupConsAccuracy is deplorable.I live at the very edge of my city, which is one city over from the ocean. On Weather.com or any other weather site, if I put in my default location as the ocean city next door, I get temps that are too cool (~5 degrees) in comparison to my location. If i use the city that I live in or the zip code, I get temps that are too warm (~5 degrees) for my location. I was looking for something more accurate and something that i can access from home or on the go so that I can find out whether or not to turn on my thermostat to cool/heat my house (the thermostat on my AC/Heating unit connects to the internet but for some odd reason doesn't have an exterior thermostat so it pulls temps from the web, which depending on the city I choose is too hot/cold for my actual location. See above for explanation.). Given my odd position, I wanted something accurate outside.In order to fix my issues, I bought this Netatmo along with 2 more additional indoor modules for my upstairs kid's bedrooms (more for the CO2 monitor than the temp). After un-boxing the devices, I was pretty happy on seeing how easy it was to setup and get connected to the internet. I noticed discrepancies in the temp and CO2 readings but I chalked it up to the fact that it had not self calibrated or rested yet and could be caused by me holding the devices as I inserted batteries. I stuck the outside unit on an outside table and didn't think much of it. The 2 indoor and the indoor base were all next to each other till I found a good home for them upstairs.A couple of days later I got a CO2 alert at work and I reopened that app and realized the horrible inaccuracy of the monitors. The 3 indoor monitors were 4 + degrees off of each other and the CO2 was off the wall different. One was registering high 400's, one was in the mid 600's, and one was alerting at over 1,000. They were all next to each other so it made no sense. I thought maybe I left a laptop next to it. When I went home there was nothing nearby and in fact, they were all in an area that was somewhat sheltered.I brought my outdoor monitor inside to verify that I didn't just get 2 bad add-on indoor monitors. Instead that action just confirmed the horrible inaccuracy of this product line as I managed to get a 4th set of different sensor readings.Screen shots are not as inaccurate as I had seen at this product's worst, but I just took them to post here right before I boxed them up to return it.My takeaway was that this is a good idea for a start towards where the professional monitors need to head towards to make it easier and cheaper for the rest of us to buy. This product however is NOT cheap enough to warrant the lack of accuracy. I expect this kind of low accuracy from a digital thermometer I pick up from a 99 cents only store. I'll just stick to the inaccurate readings that my AC/Heating unit has and stick a 2 dollar mercury thermometer with a suction cup on the outside of my patio door to replace the $350+ dollars I spent with Netatmo.