My outside readings are intermittent/temperature isn't working - how can I troubleshoot the issue?

This article applies to WS5070 (Aspect Wi-Fi Analyst) and WS5095 (Helios)

You can also use this for the discontinued WS5091 and WS5091-mkII

 The temperature and humidity are read from the sensor within the louvres on the bottom of your vane. 
As a troubleshoot we do recommend to clean this sensor and housing:

 * Remove the louvers from the underside of the vane and clean the louvers with a mild detergent solution - leave the louvers aside to dry. 
 * The sensor itself cannot get wet, please wipe this over with a dry lint free cloth and ensure any debris is cleared. (You can use canned air or a 'puff bulb' to blow out debris as well)
 * Once the louvers are dry you can put them all back onto the bottom of the vane again. Reset the vane using the button near to the mounting pole - hold the button in for 5 seconds and let it go, it will either flash 3-4 times quickly or have a 20 second pause before flashing very quickly for 2 seconds or so.
 * You should see temperature return within 3 minutes of the reset.

Outside of this there's nothing more you can do for that particular sensor. Because it's an integrated vane there's nothing you can unplug and replace in this case

If you've experienced intermittent outdoor readings, this is usually related to insects coming into the main body of the vane.

* There's 10 perimeter screws around the vane which you can undo. Flip the outdoor vane on its back - being careful to hang the wind instruments over the bench/desk. 
* You'll likely find the philips head is ok all the way around until you're doing the 4 around the rain gauge end - where the flat head will assist to give you more purchase on the screws.
* Once these are undone, carefully separate the 2 halves - the wind instruments are wired to both sides of the vane and the wires can be broken with little force, so treat it like a clam shell and open from one side, gently placing the top beside the bottom nice and close together. 
*When you look at the inside of the vane, you can now see the wire ribbon which comes from the sensor to the motherboard. You can pop the cover off the motherboard either by hand or with a screw driver if it feels tighter.

*Now with the lid off you can see the mother board cover, this may be black or beige, and can be gently jimmied up with a flat head or your hand (depending on the cover age). 

With the cover off you can see the full board and it will be immediately obvious if you have insects. Ants leave black/brown piles of a substance that looks like dirt - but it's actually woody material and VERY humid (shown below).

*This can be cleaned off with a dry brush/lint free cloth (if present), and if there is very stubborn debris then I recommend to use contact cleaner to clean as much as you can off the board -  leave the 2 halves of the vane open to dry the board back out.

*After a few hours return the cover to the motherboard and then put the vane back together.

Reset the vane and connect back to the indoor screen - providing the damage isn't too extensive then you should be able to restore function.