Quote Originally Posted by Gipsy View Post
Don't. If they're well established mature (fruit-bearing) trees their wide-spread root system will pick up enough moisture and nutrients to survive the season.

If you just planted seedlings or non-mature trees, situated in poor (hard) soil, you might help 'm a bit but don't overdo it, they need to grow 'tough', develop their root system and over watering will make them grow skinny and weak. Better to give them an extra splash 'n dash and some manure once they start growing again but that's still months away. (i.e. when the neighbours come nicking the reddish-tinted new leaves)
Very astute, Gipsy...
A more than definitive answer.