Meeting global decarbonization targets requires large-scale, low-carbon hydrogen (H₂) production around mid-century. A crucial pathway for this production is electrolysis driven by renewables, tying hydrogen production and costs to spatially varying renewable resources. The potential, variability, and complementarity of renewable resources, though, will be affected by climate change. We quantify the impact of climate change on renewable-energy generation for H₂ production globally. We use an investment and operations optimization model for hydrogen systems to estimate geographically explicit and regionally aggregated levelized cost of hydrogens (LCOHs) under historical and future climates. We find climate change could raise the cost of green-hydrogen production by up to 20% in some global locations, and about 16% of global locations could see LCOH increases or decreases exceeding 5%. Southeast Asia and Europe in particular see LCOH reductions due to climate change, while North America sees LCOH increase. Most locations, though, see modest impacts of climate change on hydrogen costs. We also find modest cost consequences from climate change for locations with active hydrogen development. Our results highlight the need for proactive investment strategies to accommodate the climatic variations affecting renewable hydrogen production, especially in countries with stricter H₂ power-grid import limits and with firm H₂ demand for industrial processes.