I am jealous of that mast and for free, WOW... and ya dome....
As for temps as mentioned already, they wont be 100% accurate to Davis spec) but to be honest, with that ground being what it is, i too would have put it up higher than the recommended height of 4-6ft, probably not the 27ft though (anemometer should be at 33ft(10m)), but certainly a 3rd or even halfway. The anemometer can be separated and this is highly recommended for more accurate temp data and for ease of maintenance but the height placement will depend on the ground cover.
If you can keep green grass around the mast then lowering the temp to recommended height would be ideal, failing that, I believe that artificial grass is used officially here in the UK by our met office at some sites, that's only so they save some money on maintenance at the sites, I feel they will read warmer than real grass but what do I know, spouse it will depend on the quality and grass height. Damn, i cannot believe that mast, I would be looking at around £1000 here in the UK for that used.