Handheld devices certainly have a place, but instructions must be followed closely, and those instructions are prone to human error (versus standalone, permanent devices). Additionally, handhelds only address one problem in the bigger picture of weather safety.
Perry Weather gives you a complete weather safety toolkit to monitor a wide spectrum of weather conditions from lightning to wind chill, keep your team on the same page through policy-driven alerts, and automatically log historical on-site conditions for simple reporting.