The Mesonet Spray Tool reports live weather conditions for pesticide applicators.
Inversions and high winds are the most important weather conditions to
assess when spraying; their icons are stoplight color-coded
() on the Spray Tool.
Though not found in label requirements, Delta T is used by some applicators for nozzle selection and for drift and volatility avoidance. An email can be sent for recordkeeping.
The Mesonet Spray Tool is supported by the South Dakota Soybean Research & Promotion Council.
How to best use this tool
Find a station:
Select a station from the dropdown menu above to get current spray conditions.
Use the station maps below to see statewide values (select layer), then select the nearest station for details.
Have copies of spray conditions sent to you via the email request form.
Refresh to keep data current (new data is updated every 5 minutes).
Use the various help buttons to find out details about what we report.
Find South Dakota's registered sensitive sites DriftWatch
The Mesonet Spray Tool reports live weather conditions for pesticide applicators. These reports are acceptable for record keeping purposes by the South Dakota Department of Agriculture.
Inversion and wind are the most important weather conditions to assess prior to spraying.
Delta T is used by some for nozzle selection and for drift and volatility avoidance.
The most important factors are displayed with stoplight color-coded icons ()
Stations update every 5 minutes. Tap the refresh button to load the latest data.
Cooler air under warmer air
Mostly night and first and last hours of daylight
Unsuitable for spraying
No Inversion, Marginal
No detectable temperature difference
Anytime, especially first two and last two hours of daylight
Marginal for spraying
Warmer air under cooler air
Rarely at night and the first and last hours of daylight
Preferred for spraying
The reported strength of inversion is the temperature (°F) of the air at 10 ft minus the temperature of the air at 40 in.
Delta T (°F) is also known as wet bulb depression. It is an indicator of droplet evaporation rate. Low delta T values correspond to cooler, humid conditions and increase drift risk by extending droplet lifetimes. High delta T values correspond to warmer, dry conditions. This increases drift risk by increasing droplet evaporation and can cause volatilization to occur.
Adapted from “Weather for Pesticide Spraying,” Bureau of Meteorology, Australian Government
Wind direction, speed and gust (mph) is measured at the ag weather standard of 10 feet. Label speeds vary, so check your label.
3 to 10 mph
11 to 15 mph
Wind speed at a height of 40 inches is calculated from 10-foot wind speed using EPA methods. This should only be used for labels that specify a boom height wind (XtendiMax, FeXapan, Engenia).