# Is it safe and efficient to spray right now?

> PulveCast tells agricultural spray operators whether conditions are safe and efficient right now: Delta T, humidity, spray drift, thermal inversion, wind and gusts, Kp index and RTK satellites. Free on Android and iOS, for drones, tractors and uniports.

- Canonical URL: https://pulvecast.web.app/
- HTML version: https://pulvecast.web.app/
- Language: en
- Last updated: 2026-09-12
- Site guide for agents: https://pulvecast.web.app/llms.txt

PulveCast reads the weather the way a spray operator does. It combines Delta T, relative humidity, spray drift risk, thermal inversion, wind and gusts — plus Kp index and RTK satellite visibility for aerial work — into one verdict for the exact hour and the exact field you are about to treat.

Free on Android and iOS. No ads, no account, no data collection you did not ask for.

## Download

- Google Play (Android): https://play.google.com/store/apps/details?id=com.pulvecast.app
- App Store (iOS, iPadOS, Apple silicon macOS): https://apps.apple.com/app/pulvecast/id6779816829
- Price: free to download. PulveCast Pro is an auto-renewable monthly subscription with an official one-month store free trial for eligible accounts. There is no lifetime purchase.

## One verdict, not fifteen numbers

Every hour of the forecast is checked against the limits of your equipment, your crop and your nozzle. The result is a traffic light you can read from the cab or from the take-off point.

- **Safe to spray** — Every parameter is inside the range you configured. Delta T is in the evaporation window, drift risk is low, there is no inversion layer, and — for aerial work — GNSS and Kp are healthy.
- **Spray with caution** — At least one parameter is close to its limit. The app names which one, explains what it does to the application, and shows how much room is left.
- **Do not spray** — At least one parameter is outside its limit. Spraying now risks losing the product to evaporation or drift, or damaging a neighbouring area.

## What PulveCast measures

Agronomic indicators first, raw meteorology second. Every card explains what the number means for your application, not just what it is.

- **Safe-to-spray verdict** — Green, yellow or red for the selected hour, computed from every parameter at once against your own limits. Tap any card to see the value, the threshold and why it matters.
- **Delta T** — The difference between dry-bulb and wet-bulb temperature: the single best indicator of droplet evaporation. Below 2 the droplets stay suspended too long; above 8 they evaporate before reaching the target.
- **Spray drift risk** — Wind speed crossed with the droplet class of your nozzle, from Very Fine to Ultra Coarse. Shows optimal, caution or avoid, so you know when to move to a coarser droplet instead of stopping.
- **Thermal inversion** — Compares the air temperature at 80 m and at 10 m from the same model. When the upper air is warmer, the spray cloud stops dispersing and can be carried far off target — the classic dawn hazard.
- **Wind speed, gusts and direction** — Hour by hour, against the ceiling of your equipment. Agricultural drone models load their own maximum wind resistance automatically.
- **Humidity and dew point** — Relative humidity against a configurable band and the dew point that tells you when condensation on the canopy will start washing product off the leaf.
- **Drone, tractor or uniport** — Pick your equipment class and the app adapts: aerial adds Kp index and satellite cards, ground drops them and keeps the agronomic core.
- **Crop presets** — Soybean, corn, sugarcane, cotton, wheat and coffee arrive with sensible thresholds, or set your own for any crop and nozzle combination.
- **Kp index and RTK satellites** — For aerial work: planetary Kp from GFZ Potsdam and the visible GPS, GLONASS, Galileo and BeiDou counts computed from orbital data for your coordinates, because a geomagnetic storm ruins pass accuracy.
- **Field tools** — Hourly forecast table, wind profile by altitude, wind compass, spray calculator, safezone map, pre-operation checklists and 24-hour Delta T and humidity history.
- **Your units, your limits** — km/h, m/s, mph or knots; °C or °F; metres or feet; 12 or 24-hour clock. Every threshold in the app can be changed to match your own operating standard.
- **Works where the signal does not** — The last loaded forecast for a location stays available offline, clearly marked, so the app still answers when you reach the far end of the property.

## How it works

1. **Pick your equipment** — Drone or tractor / uniport. For agricultural drones, choose a model and the wind and temperature limits load automatically; ground equipment hides the aerial-only cards.
2. **Pick your field and crop** — Search a location or use GPS. Choose a crop preset — soybean, corn, sugarcane, cotton, wheat, coffee — or set your own thresholds and nozzle class.
3. **Find the window** — Scroll the next hours and the next days. The traffic light and the hourly table show exactly when the field is sprayable, and the alerts tell you why it is not.

## Aerial and ground, in one app

- **Agricultural drones** — Presets for 17 models across DJI Agras, XAG, Hylio and TTA, updated remotely without an app update. Adds Kp index, GPS / GLONASS / Galileo / BeiDou visibility and RTK signal quality, because geomagnetic activity and satellite geometry decide whether your passes stay on the line.
- **Tractors and uniports** — The same agronomic core — Delta T, humidity, dew point, drift, thermal inversion, wind and gusts — without the aerial-only cards. Set your own boom height, nozzle class and wind ceiling.

## Free to use, Pro when you plan ahead

Everything you need to answer "can I spray in the next hours?" is free and ad-free. Pro adds the planning layer: more days, the hourly table, the field tools and the premium forecast providers.

### Free (US$ 0)

- Safe / caution / do-not-spray verdict for the current hour
- Delta T, relative humidity and dew point
- Spray drift risk and thermal inversion alerts
- Wind speed, gusts and direction
- Temperature, precipitation, cloud cover, visibility and pressure
- Kp index, GNSS satellite count and RTK signal for aerial equipment
- Equipment and agricultural drone presets
- Pre-operation checklists
- Offline mode with the last loaded data
- 15 interface languages and configurable units

### Pro

One month free, then the monthly price. Cancel any time in your store settings.

- Spray conditions for the coming days, not only today
- Hour-by-hour forecast table
- Wind profile by altitude layer
- Wind compass
- Spray calculator (droplet class against wind)
- Safezone map
- Crop presets
- 24-hour Delta T and humidity history
- Unlimited favourite locations
- Premium sources: WeatherAPI and Apple WeatherKit

Full detail: https://pulvecast.web.app/pricing

## Where the data comes from

PulveCast does not invent weather. It aggregates public and licensed providers and shows you which one is active.

- [Open-Meteo](https://open-meteo.com/) — Default provider: 7-day hourly forecast, wind by altitude, the 10 m / 80 m temperature pair used for thermal inversion, geocoding and time zone.
- [WeatherAPI](https://www.weatherapi.com/) — Alternative 3-day forecast for Pro subscribers, completed with Open-Meteo for the remaining days.
- [Apple WeatherKit](https://developer.apple.com/weatherkit/) — Alternative forecast of up to 10 days for Pro subscribers, requested through a server-side proxy so the credentials never reach the app.
- [GFZ Potsdam](https://spaceweather.gfz-potsdam.de/) — Planetary Kp index — geomagnetic activity that degrades GNSS and RTK accuracy.
- [CelesTrak](https://celestrak.org/) — Orbital elements for the GPS, GLONASS, Galileo and BeiDou constellations, used to compute satellite visibility at your coordinates.
- [OpenStreetMap](https://www.openstreetmap.org/) — Base map and restriction zones for the safezone map.

## Inside the app

- All field conditions on one screen: PulveCast home screen showing the spray verdict with cards for Delta T, humidity, wind and spray drift
- Crop-specific limits: Crop preset picker with soybean, corn, sugarcane, cotton, wheat and coffee, each loading its own spray thresholds
- Go, caution or stop at a glance: Spray verdict screen showing the traffic-light status and the parameters that produced it
- Thermal inversion alerts: Thermal inversion detail comparing the air temperature at 80 metres and at 10 metres
- Spray drift risk: Spray drift screen crossing wind speed with the nozzle droplet class to show the drift risk level
- Delta T and evaporation risk: Delta T detail screen with the current value against the ideal 2 to 8 degree window
- RTK satellites and solar activity: Satellite and Kp index screen listing visible GPS, GLONASS, Galileo and BeiDou counts and the geomagnetic index
- Day and hour planner: Hourly forecast table letting you scroll the coming days and pick the best spray hour

## Frequently asked questions

### Is PulveCast free?

Yes. The spray verdict, Delta T, humidity, dew point, drift risk, thermal inversion, wind and gusts, today's forecast, equipment and drone presets, checklists and — for aerial equipment — the Kp index and satellite cards are all free, with no ads and no account. Pro is an optional monthly subscription that adds multi-day planning, the hourly table, the field tools and the premium weather providers.

### What do "safe to spray", "spray with caution" and "do not spray" mean?

For the selected location and hour, PulveCast compares every parameter it has — Delta T, relative humidity, spray drift risk, thermal inversion, wind speed and gusts, temperature, precipitation, cloud cover, visibility and, for aerial equipment, Kp index and satellite count — against the limits configured for your equipment, crop and nozzle. If every parameter is within limits the verdict is "safe to spray". If one or more are close to a limit it is "spray with caution". If any parameter is outside its limit it is "do not spray", and the app names the parameter responsible.

### What is Delta T and which range should I use?

Delta T is the difference between the dry-bulb and wet-bulb temperatures, and it predicts how fast a droplet evaporates. PulveCast uses 2 °C to 8 °C as the default ideal window: below 2 the air is nearly saturated and fine droplets stay airborne and drift; above 8 a significant share of the spray evaporates before reaching the target. The band is configurable, because the right range depends on droplet size and product.

### How does PulveCast detect thermal inversion?

It compares the forecast air temperature at 80 metres with the temperature at 10 metres, taking both values from Open-Meteo so the readings come from the same model and stay consistent. When the higher level is warmer than the lower one by more than the configured threshold — 1.5 °C by default — an inversion layer is likely, and the app flags it. Under an inversion the spray cloud does not disperse vertically and can be transported a long way off target.

### Does PulveCast work for tractors and uniports, or only drones?

Both. Choose the equipment type in the settings. The agronomic core — Delta T, humidity, dew point, spray drift, thermal inversion, wind and gusts — applies to every kind of equipment. Selecting ground equipment hides the aerial-only features (drone presets, RTK and GPS settings, Kp index and satellite cards) so the screen only shows what matters to you.

### Which agricultural drones are supported?

PulveCast ships presets for 17 agricultural models across DJI Agras, XAG, Hylio and TTA, including the Agras T10 through T100, XAG P100 Pro, P40 and V40, Hylio AG-130 and AG-230, and TTA G200 and M6E-1. The list is updated remotely, so new models appear without an app update. If your machine is not listed, choose the custom option and enter the wind and temperature limits from its manual.

### Where does the weather data come from?

Open-Meteo is the default provider and supplies the 7-day forecast, the wind profile by altitude and the 10 m / 80 m temperature pair used for thermal inversion. Pro subscribers can switch to WeatherAPI (3 days, completed with Open-Meteo) or Apple WeatherKit (up to 10 days, through a server-side proxy). The Kp index comes from GFZ Potsdam, satellite positions are computed from CelesTrak orbital elements, and the safezone map draws restriction zones over OpenStreetMap.

### Why does the forecast sometimes disagree with what I see in the field?

A forecast is a numerical model output for a grid cell, not a measurement at your headland. Wind especially varies over short distances near tree lines, buildings and terrain, and gusts are inherently hard to predict. Use PulveCast to choose the window and to catch the conditions you cannot see — inversion, Delta T, drift risk — and confirm wind and humidity on site before you open the boom.

### Does the app work without internet?

Partly. The last forecast loaded for a location is cached on the device and shown with an offline badge, so you can still consult it in the field. Refreshing the forecast, the Kp index and satellite data requires a connection.

### Do I need an account? What data is collected?

There is no account, no sign-in and no forum. Equipment, crop presets, thresholds, checklists, favourite locations, language and units are stored locally on your device. Location coordinates are sent to the weather providers to fetch a forecast and are not stored on our servers. Diagnostics are aggregated and anonymous. The privacy policy has the full detail.

### How does the Pro subscription work, and can I use it on more than one device?

Pro is an auto-renewable monthly subscription processed by Apple or Google. Eligible store accounts are offered an official one-month free trial by the store. It renews every month until you cancel it in your App Store or Google Play settings. Purchases are validated server-side, so Pro is tied to your store account and follows you to any device signed in with it — use "Restore purchases". There is no lifetime or one-time purchase.

### Is there a web version of PulveCast?

No. PulveCast is distributed through Google Play and the App Store for Android phones and tablets, iPhone, iPad and Apple silicon Macs. This site is the product page, not the application.

## Other pages

- [Home](https://pulvecast.web.app/) — PulveCast tells agricultural spray operators whether conditions are safe and efficient right now: Delta T, humidity, spray drift, thermal inversion, wind and gusts, Kp index and RTK satellites. Free on Android and iOS, for drones, tractors and uniports.
- [Pricing](https://pulvecast.web.app/pricing) — PulveCast is free and ad-free: verdict, Delta T, humidity, drift, thermal inversion, wind and today's forecast. Pro is a monthly subscription with a one-month free trial that adds multi-day planning, the hourly table, field tools and premium weather sources.
- [About](https://pulvecast.web.app/about) — PulveCast is built by independent developer Renan Rafael Bertoldo in Brazil. Learn why the app exists, how the spray verdict is computed from Delta T, drift, inversion and wind, and which data providers it relies on.
- [Contact](https://pulvecast.web.app/contact) — How to reach PulveCast: support email for bugs, feature requests and privacy questions, store reviews, and the response you can expect from an independent developer.
- [Privacy](https://pulvecast.web.app/privacy) — How PulveCast collects, uses and protects data: location handling, on-device preferences, diagnostics, purchase validation, third-party providers, retention and your rights under GDPR and LGPD.
- [Terms](https://pulvecast.web.app/terms) — Terms of use of the PulveCast mobile application: service description, the Pro subscription, data sources and disclaimers, operator responsibility, and availability.

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PulveCast is a mobile application; this site is its product page and has no public HTTP API.
Machine-readable index of this site: https://pulvecast.web.app/llms.txt · https://pulvecast.web.app/llms-full.txt