Using Spraying Drones According to Weather Conditions

Weather is one of the biggest factors in drone spraying results. If one of two identical applications falls on a windy, hot afternoon, much of the product evaporates or drifts to the neighbouring field before reaching the target. This guide shows how to read the weather and when to spray.

How Weather Affects Spraying

Wind

• Wind speed and direction determine where droplets land.
• As a rule, avoid spraying when wind exceeds 3 m/s (about 10 km/h).
• Postpone if the wind blows towards a sensitive area such as other crops, beehives, homes or water.
• Completely still air is also risky: during temperature inversions fine droplets can hang in the air and travel far.

Rain

• Rain shortly after application washes off the product.
• Check the rainfastness period on the label and hourly forecasts.
• Postpone if rain is likely.

Temperature and humidity

• High temperature and low humidity make droplets evaporate quickly.
• As a starting point, 15-25°C and relative humidity above 50% are considered suitable.
• Some products can scorch plants on very hot days; read the label.

Planning the Application

Pick the right time

Early morning and late afternoon, when wind is usually calm, are best. Avoid the midday heat.

Follow hourly forecasts

Check hourly wind, rain and temperature on the day. A handheld anemometer in the field is very useful.

Adjust drone settings

• If wind picks up slightly, fly lower and use coarser droplets.
• Plan edge passes according to wind direction and leave a buffer next to sensitive areas.
• Make sure radar and positioning systems are working.

After Spraying

• Check efficacy in the field over the following days.
• Look for signs of drift on neighbouring land.
• Clean the tank, nozzles and propellers.
• Record the weather on the day for future planning.

See the full workflow in How to Use an Agricultural Drone. Explore the DJI Agras T50 and other models on our spraying drones page.