In the new Hobbit movie, the warg riding orcs attack in daylight, which according to Tolkien's books should not be possible. Any speculations how this might be explained anyway? In the Lord of the Rings movies there were the Uruk Hai who could travel in daylight (as in the books). But these orcs seemed to be of a different kind.
Those were Hunter Orcs:
The fast-moving and fanatical Hunter Orcs serve as the right hand of Azog, a relentless band who will stop at nought to slay his quarry.
One of the Hunter Orcs ,Yazneg, was killed by Azog after he failed to capture Thorin, so they were clearly under a lot of pressure. Compared to Azog's wrath the Hunter Orcs possibly considerd sunlight to be the lesser evil.
Or maybe this breed, like the Uruk-hai, can indeed withstand the sunlight better
(Because this is 'non-canon' there seems to be very limited information)
In fellowship of the ring they twice mention that orcs can't move in sunlight. "Saruman is breeding an army in the caverns of isengaurd. An army that can move in sunlight". "By nightfall this hill will be swarming with orcs" (after the exit the mountain of moria). The new hobbit films don't offer an explanation but most of the movie there appears to be much cloud cover. This could serve as an explanation