I'm also going to DLP on the 10th, so might see you there!
I'm currently using
www.meteoprog.co.uk for long range forecasts - its currently got Paris weather up to 11th July (forecasting sunny, 27-28C for both 10th and 11th).
I used to use Metcheck, but that site seems screwed up at the moment.
In the hotels at Disney, they stick up forecasts for the next day in reception - trouble is, when I went, they were wrong every day.
But I would take all weather forcasts with a pinch of salt - there was a study done some years ago, and it found that if you assume the weather tomorrow is going to be the same as the weather today, then you will be right more often than the weather forcaster!