Heat Safety: Heat Index & WBGT

Review by eFreeware

Heat Safety is a weather app from Qvyshift LLC that deals with one narrow subject: how hot it actually feels at a US work site, and what that means for the people working there. Rather than a general forecast, it reports heat index and wet bulb globe temperature, the two measures that occupational and athletic heat planning tends to run on. It is free, it carries ads, and it has been on Google Play since December 2022.

The reason to consider it is the pairing of those measurements with risk categories. Heat index values are sorted on the OSHA-NIOSH three-category scale, and WBGT values follow the US Army standard, so a number arrives with a band attached rather than leaving you to interpret it. For someone who has to decide whether a crew keeps going or takes a break, that framing is the point of the app.

It has drawn a 4.8 average from 330 ratings, which suggests the people who need this sort of tool are getting what they came for. The install figure, over 10,000, is modest, and that fits a utility built for a specific job rather than a broad audience.

What wet bulb globe temperature tells you that a thermometer does not

The app centers on wet bulb globe temperature, or WBGT. It is a composite measure that heat-safety programs use when deciding how much work is safe in direct sun. The app reports psychrometric wet bulb globe temperature for locations in the USA, alongside the plain temperature and humidity readings that feed into it.

Heat index is the second measure, and it will be the more familiar one to most people. It captures how hot it feels once humidity is factored in. The app displays the current heat index value and applies the OSHA-NIOSH three-category scale to it, so the reading comes with a risk band.

Both measures appear as current conditions and as forecasts, giving four days of outlook for heat index and WBGT. That combination is what makes the app useful for planning rather than just reacting: you can see a hot afternoon coming and move a task earlier, or schedule a rest rotation before the day turns.

Forecast and weather data come from the National Weather Service. Presenting official data in a heat-safety frame is the sensible arrangement for this kind of tool.

Temperature, humidity and the risk bands around them

Beyond the two headline measures, the app shows current temperature and current humidity. Having them on the same screen as the derived values helps you understand why a day feels worse than the thermometer suggests. A dry 95-degree afternoon and a humid one are very different propositions.

The risk categorizations are the app's other main contribution. Heat index categories come from the OSHA-NIOSH scale, and WBGT categories follow the US Army standard. Two separate scales, each applied to its own measure, means the app is not forcing one framework onto both numbers.

The developer lists the intended audience as coaches, managers and workers. That covers a fairly wide range of situations: someone running a youth practice, a supervisor coordinating a landscaping or construction crew, or an individual who simply wants to know when a hot day has crossed into territory worth taking seriously.

The health outcomes the app is built around are the familiar ones for heat exposure: heat stroke, heat exhaustion, rhabdomyolysis, heat cramps and heat rash. The app's role is recognition rather than treatment. It gives you the conditions and the risk band; the response, in the form of hydration, rest breaks and scheduling, is down to you and whatever protocol your workplace or program follows.

What the app asks of you

The requirements are light. There is no login, no registration and no subscription, which matters for an app that might be opened by several people on a crew or handed around a coaching staff. Nothing stands between installing it and reading a heat index value.

The app is free and ad-supported, with the developer describing the ads as occasional. A one-time in-app purchase removes them. There is no subscription and no tiered pricing, just an optional one-time payment to remove ads.

The one real constraint is geographic. It reports heat index and WBGT for US locations, drawing its weather data from the National Weather Service. If the site you care about is outside the United States, the app may not cover it.

The app was last updated in October 2026, and the notes for that release describe behind-the-scenes changes to keep things running smoothly rather than new features. For a utility whose value rests on a stable data feed, that kind of maintenance is what you would hope to see.

Fitting it into a workday

The most obvious way to use the app is as a morning check. Before a crew arrives or a practice starts, the four-day heat index and WBGT forecasts let you look at the day ahead and decide whether the schedule needs adjusting. Moving a strenuous task to an earlier slot is easier to arrange the night before than at noon.

Through the day, the current readings serve a different purpose. A mid-morning reading is not a reliable guide to early afternoon. Checking again before a demanding stretch of work gives you a current basis for deciding on rest breaks.

The risk categories are what make those checks quick. Rather than remembering thresholds, you read the band and act according to whatever policy applies to your site or program. For a coach or manager who has to make that call in front of other people, having the categorization already applied removes a step.

It is worth being clear about the app's place in a heat-safety routine. It supplies conditions and risk levels. The developer's framing is prevention through recognition, which puts the app at the front of the process, informing the decisions that follow.

A focused tool for US heat planning

Heat Safety does one job and does it without asking much in return. There is no account to create and no subscription to maintain.

The case for installing it rests on whether you make heat decisions for other people or for yourself outdoors. The design suits coaches, managers and workers: quick readings, standard categories, and forecasts for planning ahead.

The trade-offs are the ones the app itself sets. It is ad-supported unless you pay once to remove them, and its coverage is US locations drawing on National Weather Service data. Anyone planning work in the heat within that footprint will find the measurements and the risk bands they need in one place.

If your day involves deciding when it is too hot to keep going, this is a straightforward way to get that answer from official data.

What's new in version 3.4.1

Behind-the-scenes changes to keep things running smoothly.