Spray Window Advisor
Find the best days to spray based on wind, rain, humidity, and inversion risk. Enter your details below and get a clear 7-day outlook.
The Science Behind Spray Windows
Applying at the wrong time doesn't just waste product — it can damage neighboring crops, harm the environment, and cost you a second pass. Here's what drives the recommendations above.
Wind speed matters most
Winds above 10 mph cause drift that wastes product and risks off-target damage. Below 3 mph can signal a temperature inversion.
Humidity affects absorption
Moderate humidity (40–70%) helps droplets stay liquid long enough for plant uptake. Too low and they evaporate; too high and they run off.
Temperature inversions trap spray
When warm air sits above cool air, fine droplets hang in a concentrated layer and drift unpredictably — sometimes for miles.
Rain washes away product
Most herbicides and fungicides need 1–4 hours of dry time after application. Rain within that window means reapplication and added cost.
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This tool provides general guidance based on typical weather patterns and agronomic best practices. It does not replace real-time weather monitoring, product label instructions, or professional agronomic advice. Always consult your product label and local extension office before making application decisions. Greenfield Partners is not liable for outcomes based on this tool's recommendations.