Zelus WBGT

Zelus WBGT: Real-Time Heat Safety Monitoring

Zelus is a patented system that delivers hyperlocal Wet Bulb Globe Temperature (WBGT) readings, lightning alerts, AQI data, and compliance documentation tools — without expensive weather hardware.

WBGT is not the same as temperature or heat index. It accounts for the major environmental factors that affect heat stress, including temperature, humidity, wind, and solar radiation.

WBGT is widely used in athletics, military, workplace safety, and heat illness prevention programs because it provides a more complete picture of heat stress risk.

With Zelus, you can monitor the conditions that matter, save important safety data, and document your decisions in the field.

What Zelus Monitors

• Real-Time WBGT
Hyperlocal readings tied to your GPS location or saved locations

• Compliance Documentation
Save safety data with date, time, location, and signature stamps to support accountability, compliance, and internal review

• Saved Locations
Track fields, campuses, job sites, facilities, and event locations

• Lightning Detection
Timely alerts for your area, available with All-Star in the United States only

• Air Quality Index (AQI)
Real-time AQI data, available with All-Star where supported

Who Uses Zelus

Zelus is used by:

• Athletic departments
• Youth sports organizations
• Construction crews
• Utility teams
• Military organizations
• Safety officers
• Outdoor teams that need practical heat and weather safety information

Plans

Zelus is available through a 7-day free trial followed by a paid subscription.

The free version of Zelus is being discontinued on June 1, 2026. Existing free users can start a 7-day trial in the updated app.

• Club
Core WBGT monitoring and saved locations for individual users

• Pro
Everything in Club, plus alerts, compliance documentation, and WBGT forecasts

• All-Star
Everything in Pro, plus lightning detection and AQI monitoring

Subscriptions

Payment is charged to your Apple ID account at confirmation of purchase.

Subscriptions renew automatically unless canceled at least 24 hours before the end of the current billing period.

You can manage or cancel your subscription in your Apple ID Account Settings at any time.

Free trials convert to a paid subscription at the end of the trial period unless canceled beforehand.

A Few Things to Know

• Heat illness can occur at any temperature. Always have a plan in place to prevent, recognize, and respond to heat illness.

• Zelus may use your phone's last known GPS location. For the most accurate results, use saved locations.

• All environmental measurement systems can occasionally produce readings outside an expected range. Users should always apply their own judgment and follow applicable policies, procedures, and local conditions.

• Zelus WBGT may provide less accurate readings in certain environments, including enclosed tennis courts or large black surfaces such as parking lots.

• Lightning detection is not 100 percent.