Making illumination light sources become comfortable to the human eye is a long-term effort, which justifies the current research on warm white-light-emitting diodes (w-LEDs). In this work, a novel phosphor for w-LEDs, namely SrGa12O19: Dy3+(SGO: Dy3+), with a low-color temperature (CT) was designed and synthesized. The crystal structure, the luminescence properties, the thermoluminescence properties and the stability of SGO: Dy-3(+) were investigated. We demonstrate outstanding luminescent characteristics and excellent stabilities. The intensity of emission light keep remained when excited by a flickering light source with a chopping speed or off-time of a few seconds, which indicates that the SGO: Dy3+ phosphor has anti-flicker properties that will be useful for potential applications, as LEDs driven by alternating current (AC-LED). The chromaticity coordinates and the correlated color temperature (CCT) of SGO: Dy3+ phosphors with different Dy3+ concentrations are close with an optimal doping at 4.00 mol% Dy3+ for chromaticity coordinate (0.4269, 0.4348) and a lowest CCT of 3361 K. The perfect weatherability of this phosphor was also confirmed since the phosphorescence intensity and the color were stable at high temperature and in a high humidity environment. The performance obtained shows that SGO: Dy3+ is a suitable candidate for illumination sources that are beneficial to human health.