In this gear guide, we review 16 models of waterproof mitten shells ("rain mitts") weighing less than 4 ounces (113 g) within the primary context of 3-season backpacking.
The Outdoor Research Flurry Sensor Glove (2.5 oz / 71 g, $40) is the warmest glove I've found that I can use effectively with a smartphone.
The Arc'teryx Venta Mitten and its cousins, the Venta Glove and Venta AR Glove, are windproof, weather-resistant active insulation layers aimed at users participating in high-output activities in moderately cold temperatures.
Lightweight Backpacking Gear for Cold Winter Temperatures (Two-Layer Systems, Vapor Barriers, and Really Puffy Stuff)
Lightweight backpacking gear for winter temperatures: two-layer insulation systems, vapor barrier systems, and really puffy stuff.