The best time to plant maples and conifers is in the late winter or early spring instead of the summer heat.  They will undergo less stress and have a chance to establish a root system before winter cold and winds.  The first year it is  best to protect newly planted trees from weather extremes of heat, cold, drought and wind.

The following Oregon State University article explains the best practices of planting conifers. https://today.oregonstate.edu/news/five-tips-properly-planting-conifer-tree

Thank you for your question.

Is it best to leave the potted conifer & maples  in pots until winter/spring rather than get them into the ground now? Temps here on the coast are mild but the wind may be a problem..

It is best to leave the potted trees in the pots at least until late fall when the rains begin.  If you plant them in the ground now they will not have time to form a good root system and will require more care regarding watering during heat events.  Place the pots in a partially shaded area where they will not be subject to the direct intense morning or evening sun.  If you do not have a shaded area consider creating one with some shade cloth.

Trees in pots can dry out fast if the potting medium is fast draining.  If the soil feels dry at the depth of one inch you need to water.  Check the pots for proper drainage and water until the water flows all the way through the pot.  Do not have the pot in a saucer or vessel that will cause it to be in standing water.

Thank you.