Why won't indoor sensors work when pointed out the window?

[brumster (Paul)]

There are plenty of options for outdoor sensors and they will almost certainly perform better than a standard ST motion sensor placed outside.

Have look here:

FAQ: Do you know of an outdoor motion sensor?

I am looking for outdoor motion sensors to monitor my yard. I bought a pair of the Aeon Labs Aeotec Z-Wave Multi-Sensor and am quite unhappy with them. Even on the lowest sensitivity setting it randomly sends alerts, some perhaps due to clouds changing the lighting (even though PIR is not supposed to be susceptible to this) and others I can’t explain at all. With several false alerts a day this thing is just useless. The Smartthings Motion sensor works great, I have some in my house, but it is indoor rated only. The Schlage / Nexia motion sensor is also indoor use only. I am hoping someone has come across an outdoor rated motion sensor they have been able to pair with the Smartthings hub.