We use local weather to find the hottest week of the last year so your system won't come up short in summer.

What your controller runs today for this zone (e.g. 240 minutes = 4 hours).

How many days between waterings on this zone (e.g. 4 = irrigate every 4 days). We apply that fraction of the peak weekly water each time the zone runs.

Micro-sprinklers use spec-sheet throw diameter vs your tree canopy; drip sizes by flow (GPH) only.

Sprayer flow and throw come from the parts catalog at your PSI.

How evenly water reaches each tree (85% is a fair guess for maintained drip).

Share of applied water that should drain below the roots. 15 means the tree's need is divided by 0.85. Often 0–15%.