Sheltering is of two kinds:
By using an umbrella, the roof of a vehicle, an aeroplane, and the like. This is forbidden for men, in a state of ihram, if the shade is above the head. However, it is allowed to be in the shade of a moving cloud.
Evidently (adhhar), there is no objection to the shade covering one side of the body only. For example, pedestrians walking beside a car producing a shade on one side.
As a matter of precaution, riders must avoid shade, unless the shade, produced from both sides, is so short that it does not cover the head and chest of the pilgrim.
By being under fixed objects like the shade of walls, tunnels, trees, mountains, etc. Evidently, being under such shade is allowed for a pilgrim, in a state of ihram, whether riding or on foot. There is no objection to protecting oneself from the sun with one's bare hands, although it is advisable to refrain from it, as a matter of precaution.
By "avoiding cover, or shading", we mean no protection should be used against the sun and, as a matter of precaution, the rain. However, there is no objection to protecting oneself from wind, heat, cold, etc., albeit it is advisable not to embark on it, as a precautionary measure.
Yet, there is no objection to using a covered bus during the night, even if it is not raining, as a matter of precaution. That is even with the knowledge that it may provide protection against wind.
The prohibition of resorting to shading, discussed above, is confined to walking and covering a distance. Once the pilgrim, in a state of ihram, arrives at a place, be it that he uses for accommodation or not, there is no objection to his moving under shade.This is treated in the same way as if the pilgrim was en route, in that he can remain in the shade of a house in which he is resting, or meeting friends, i.e. it is apparent that he is permitted to be under shade.
The question, though, still remains as to whether the pilgrim is permitted to be under the shade of a moving object, once he settled and went about his business. Say, he had arrived in Makkah and wished to proceed to the Holy Mosque for tawaf and sa'y, or once in Mina, he wished to proceed to the place of sacrifice or Jamarat. It is very problematic (mushkilun jiddan) to pass a ruling, permitting it. Accordingly, and as a matter of precaution, one should avoid doing so.
There is no objection to women or children sheltering in the shade, and even men when it is necessary.
The kaffarah for being under shade is a sheep, whether the breach was deliberate or out of necessity. If it is repeated, a sheep should, as a matter of precaution, be given for each day of the breach, although it is evident that there is only one penalty for the entire state of ihram.