So I've had my P3 for about a week now but have only flown twice due to the wind(and rain) and I was wondering which site i should trust.

http://www.uavforecast.com/ says it will be 28 mph at 1000 ft however https://www.windyty.com says it will be 16mph at the same time,altitude and location. which one should I trust? Or is there another site I should trust?

I use informations i have learned during my Paragliding training, Paraglider are very sensitive to Air movements, like our valuable birds.

On the heights we are flying you will always get random Forecasts.
I use Free "AeroWeather" app (iPhone/Android) to get METAR for current and TAF for Forecast Weather condition of the Local Airport, just matter to get general overview.
If you are near to a Paragliding or other Air sport site you can maybe get they Weather Station Data
For France for example there is a Website with all Stations: http://www.balisemeteo.com

On site you will normally find other Weather conditions of what you have in the Forecast regarding Wind direction and force, for this i observe Flags on Buildings, cranes (when not in operation), Clouds, and Trees to get a idea of what is going on.

In general you can say if Trees are moving then it's too windy to fly, same if it's very Hot or you have any high Temperature difference that can create Air movements you can't predict
In these conditions our birds will try to compensate something he is not aware of, so Devil Murphy will take over.

On Paragliding Websites you can find detailed explanations about Meteorology, it's a bit hard to get in but it can save your investment.
Some samples:
Beaufort scale: http://www.paragliding.org/book/en/6-3.htm
Thermals and Leeside problem: http://www.paragliding.org/book/en/8-1.htm
Sea Breeze: http://www.paragliding.org/book/en/6-4.htm
Atmospheric Waves http://www.paragliding.org/book/en/6-6.htm

Paragliding proverbes:
- It's better to be on the ground and regret not to be in the Air, as to be in the Air and regret not being on the ground.
- There are two types of Pilots, they who made it into the tree and these who didn't yet.

..ok this was now a longer post, but hope it will help saving some birds.

bebbi is correct in many of this statements.....if the trees are blowing, stay grounded.

In terms of actual wind speed, forecasts of 8-10 MPH at the ground level can be doubled at altitude or in certain valleys. The Phantom 3 can actually fly in those winds, but a gust at 25 or over could very well blow it away (mine blew away this way, but luckily RTH brought it back).

As a sailor I have become more aware of the micro-climates which can cause high winds locally. You should be familiar with the general wind currents in your area as well as the land and water features that could concentrate them. We have some areas (Coastal Rhode Island) which are perfectly designed like nozzles - the wind comes from the south and then hills on the side of the wide strait concentrate it. This results in winds 50% stronger than nearby.

As i am also a hot air balloon pilot i can tell you that low altitude winds are very local, and any forecast you see, even from the closest airport, will be pretty much useless.  The other factor to consider is thermal activity which is the movement of air coming from uneven heating of the ground over something like a plowed field or a lake or pond.  Balloons are flown in the hour after sunrise or before sunset because when the sun is low thermals diminish.  

I've flown the P3 in conditions that would ground a balloon.  The GPS and visual stability is just amazing.

Yes GPS and visual stability is amazing,
for some people to well, because they fly the bird in bad weather conditions and does not see how much the machine has to work to stay "nailed"