I'm not sure what types of high temperatures you are expecting , but pvc for sprinklers is commonly used, easy to install and easy to find at home improvement stores. cpvc can be used as well. More of a concern than heat is freezing, where both can crack and burst if not drained down properly each year before winter.
Becoming more popular is pex, though it requires a specific tool and fittings to make connections. The tool and fittings are becoming more commonplace in home improvement stores as well. A benefit to pex is that it can freeze and typically hold true until it thaws unless a fitting/connection is frozen.
There are plenty of installation help videos for all of them on the internet for which ever you choose.
Please keep in mind that irrigation systems need back flow protection devices installed to protect the house's clean water from contaminants outside and in the soil. If one isn't already in place, you should contact a registered plumber who is backflow certified to install the appropriate device to keep you and your family safe.