Forecast for spraying
When should I spray?
Hourly suitability scores for your area over the next 7 days, from wind, rain and air dryness — the same rules the drone booking system uses.
New: My Field Weather
Rain, wind, temperature, hourly, 7 days and a rain map around the plot — in one app
See weather ›How the score works
Wind at nozzle height 3–12 km/h
Wind at 10 m (what most weather apps report) is converted to about 2 m, where the nozzles are. Above 15 km/h droplets drift off the plot; too calm and they hang in the air.
No rain within 2 hours after spraying
Rain soon after spraying washes the product off the leaves. As a screening rule we check the spraying hour and the two hours after it — the time each product actually needs is on its label.
Delta T no higher than 8–10°C
The difference between air temperature and wet-bulb temperature shows how fast droplets evaporate. It combines heat and humidity in one number. Above 10°C droplets dry before they reach the leaf.
Watch out for still air at dawn and dusk
Calm wind under a clear sky creates a temperature inversion. Fine droplets hang in the air and can travel to neighbouring fields, so these hours lose points.
Daylight flying only
We use the real sunrise and sunset for that point, not fixed hours.
Confidence is shown too
When the source provides an ensemble forecast, we count how well its runs agree on rain and wind. The current main sources (MET Norway + Thai Meteorological Department) have no ensemble, so confidence is estimated from how many days ahead the slot is. Uncertain cells get a dashed border. Check again closer to the day.
Weather forecast: MET Norway (CC BY 4.0) and Thai Meteorological Department · Measured rain: National Hydroinformatics Data Center (thaiwater.net), Hydro-Informatics Institute
