Abstract An evaluation‐classification‐downscaling‐based climate projection (ECDoCP) framework is developed to fill a methodological gap of general circulation models (GCMs)‐driven statistical‐downscaling‐based climate projections. ECDoCP includes four interconnected modules: GCM evaluation, climate classification, statistical downscaling, and climate projection. Monthly averages of daily minimum ( T min) and maximum ( T max) temperature and daily cumulative precipitation (Prec) over the Athabasca River Basin (ARB) at a 10 km resolution in the 21st century under four Representative Concentration Pathways (RCPs) are projected through ECDoCP. At the octodecadal scale, temperature and precipitation would increase; after bias correction, temperature would increase with a decreased increment, while precipitation would increase only under RCP 8.5. Interannual variability of climate anomalies would increase from RCPs 4.5, 2.6, 6.0 to 8.5 for temperature and from RCPs 2.6, 4.5, 6.0 to 8.5 for precipitation. Bidecadal averaged climate anomalies would decrease from December‐January‐February (DJF), March‐April‐May (MAM), September‐October‐November (SON) to June‐July‐August (JJA) for T min, from DJF, SON, MAM to JJA for T max, and from JJA, MAM, SON to DJF for Prec. Climate projection uncertainties would decrease in May to September for temperature and in November to April for precipitation. Spatial climatic variability would not obviously change with RCPs; climatic anomalies are highly correlated with climate‐variable magnitudes. Climate anomalies would decrease from upstream to downstream for temperature, and precipitation would follow an opposite pattern. The north end and the other zones would have colder and warmer days, respectively; precipitation would decrease in the upstream and increase in the remaining region. Climate changes might lead to issues, e.g., accelerated glacier/snow melting, deserving attentions of researchers and the public.
Key Points An integrated framework for projecting temperature and precipitation in a large unregulated continental river basin in Canada: Athabasca Colder days in north end, less precipitation in the upstream, and warmer and wetter days in the other regions in the 21st century Climate changes may lead to issues, e.g., accelerated glacier/snow melting, deserving attentions of research community and the public