It's hot and many trees need help in the heat.  There's several ways you an help, however many require prior preparation:

?Successful Irrigation is crucial for cooling, both unser-canopy and over-canopy  Using the Irrigation systems strategically will achieve best results ?

Mulching tree berms, also improves soil and tree health ?

Monitoring – Soil moisture and air temperatures ?

The use of Protectants(reflectants) products can be used to alleviate the stress of heat, usually provides a few degrees relief ?.  Antitranspirants can make it worse by shutting down stoma and reducing cooling transpiration

Cover cropping and hedgerows increase humidity and evaporative cooling. 

Watch a video produced by the CA Avocado Society for what can be done in preparation and now:

https://www.youtube.com/watch?v=E7EWU0tAMVY