We have a small-ish farm in Oregon. We religiously watch the wind before spraying for two reasons: 1) Chemicals are extremely expensive and chemicals that drif

We have a small-ish farm in Oregon. We religiously watch the wind before spraying for two reasons: 1) Chemicals are extremely expensive and chemicals that drift off the field are wasted, not to mention that in high winds you can't be confident in good coverage (unless you just dramatically increase your spray amount, which, see again re: cost). 2) Despite our extreme care, we have had regulatory bodies called on us by neighbours about drift (investigation exonerated us). Thus we have both an internal, selfish reason to not spray during high wands and an external reason to not spray during high winds. I can't speak to other areas of the country (let alone the world) or other kinds of farming.