Ride Leaders have the option to cancel a ride if temperatures during the ride are expected to be less than 40 degrees or the road conditions are unsafe, and if the heat / humidity index during the ride is expected to be 90 degrees or above.
In COLD WEATHER you lose the most heat through the extremities (head, hands, feet) and you have the wind chill factor which makes you feel colder. When riding in cold weather be aware of symptoms of hypothermia and take rest breaks at places w/shelter, warm drinks, etc., but be careful not to stop for an extended period of time because you will lose your body heat.
In HOT WEATHER, Clothing is rarely the problem, water is! Make sure to drink plenty of liquid and watch your urine, it should be pale yellow or clear. Know the signs of sunstroke, heat exhaustion and dehydration (cramping, disorientation, lightheadedness, etc.) Your rest stops should be frequent and in the shade.
When you get caught in the RAIN metal surfaces such as metal deck bridges and manholes are slippery when wet, as are painted road surfaces. Stay with the group in the rain because motor vehicles can see a group of riders better in the rain than a single rider. Make sure to avoid riding in puddles when you cannot see the road surface beneath. For better visibility wear your HBC safety vest and use head and tail lights.