The Mesonet Spray Tool reports live and forecast weather critical to pesticide applicators.
Applicators can use the "Record by Email" button to request spray weather conditions from any station in the last 7 days.
Wind at 3 ft, inversion, and ΔT are stoplight color-coded to provide guidance to the applicator ()
Stations update every 5 minutes. Tap the refresh button to load the latest data.
3-ft Wind Speed
Calm
2 mph
3 to 10 mph
11 to 15 mph
16+ mph
All wind reports in the Mesonet Spray Tool are at a height of 3 feet for ground applications which can range from
28% to 85% of a standard height wind depending on conditions. For maximum applicability across a station's coverage area,
the 3-ft wind is derived using EPA methods from measurements made at a greater height (either 10 or 33 feet).
Inversion
Inversion, Unsuitable
Positive
No Inversion, Marginal
Zero
No Inversion, Preferred
Negative
A temperature inversion (inv) is a condition when cooler air is trapped under warmer air. It is determinded
from the vertical temperature difference (either 3 and 10 ft or 6 and 33 ft). Inversions allow concentrated
clouds of pesticide to be transported long distance with being broken up. Inversions are closely tied to times
when the sun is unable to heat the earth's surface: during the night and the first/last hour of the day.
Delta T (ΔT)
Low
0-3°F
Preferred
4-14°F
High
15-18°F
Very High
19+°F
ΔT is the term used in the pesticide applicator community to refer to wet bulb depression.
Roughly speaking, it is the difference between the temperature of the air and a water droplet suspended in it (°F).
It combines the effects of both temperature and humidity to give a good picture of the evaporation rate of a
pesticide droplet. At low ΔT values, low evaporation rates mean that droplets can travel extended
distances increasing drift risk. At high ΔT values, increased droplet evaporation (in the air and on surfaces)
can reduce product effectiveness. All else being equal, the impact at high ΔT values is less pronounced
when using COURSE or greater nozzles. ΔT is not restricted on labels in the US.
Adapted from "Weather for Pesticide Spraying", Bureau of Meteorology, Australian Government
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The following data is available:
To request another record, use the "Record by Email" tab. Refresh the page to get access to the most recent data.
About the Mesonet Spray Tool
The Mesonet Spray Tool provides live reports and forecasts of weather critical to pesticide applicators including 3-ft wind, inversion,
and ΔT. Current conditions update every five minutes. Forecast updates every hour.
Reports for any station from any time in the last 7 days can be sent to the user using the "Record by Email" button.
3-ft Wind: Direction and speed (mph) at boom height for ground applications (these can be significantly lower than standard wind speeds)
Inversion: A positive vertical temperature difference indicates an inversion (Yes/No/Marginal or Y/N/M)
ΔT (DeltaT): Used to estimate droplet evaporation rates
Precipitation
Today: measured since midnight
Today's forecast: remainder of the day
Tomorrow's forecast: 24-hour forecast
The Mesonet Spray Tool is made possible by the South Dakota Soybean Research & Promotion Council.
