If you are serious about your training, you may want to invest in a sport watch. Since the model is waterproof, you don't have to worry when it's raining outside.
From OnBuy
Polar M430
The Watch Hut
Unisex Polar M430 Bluetooth Wrist HR Smart Activity Tracker Alarm Chronograph Watch 90064407 - LCD / White
Watch Shop
Polar M430 Running Smartwatch - LCD / White