Weather forecasting requires both deterministic outcomes for immediate decision-making and probabilistic results for assessing uncertainties. However, deterministic models may not fully capture the spectrum of weather possibilities, and probabilistic forecasting can lack the precision needed for specific planning, presenting significant challenges as the field aims for enhance accuracy and reliability. In this paper, we propose the Deterministic Guidance-based Diffusion Model (DGDM) to exploit the benefits of both deterministic and probabilistic weather forecasting models. DGDM integrates a deterministic branch and a diffusion model as a probabilistic branch to improve forecasting accuracy while providing probabilistic forecasting. In addition, we introduce a sequential variance schedule that predicts from the near future to the distant future. Moreover, we present a truncated diffusion by using the result of the deterministic branch to truncate the reverse process of the diffusion model to control uncertainties. We conduct extensive analyses of DGDM on the Moving MNIST. Furthermore, we evaluate the effectiveness of DGDM on the Pacific Northwest Windstorm (PNW)-Typhoon satellite dataset for regional extreme weather forecasting, as well as on the WeatherBench dataset for global weather forecasting dataset. Experimental results show that DGDM achieves state-of-the-art performance not only in global forecasting but also in regional forecasting scenarios. The code is available at: https://github.com/DongGeun-Yoon/DGDM.