We investigate variations in 137Cs activities, temperature and rainfall with time and predict how climate change will interact with existing 137Cs anomalies. We focus on several case-studies affected by distal fallout from Chernobyl; the Kymijoki watershed in Finland, Gävle in Sweden and Bavaria in Southeast Germany. In addition, we investigate 137Cs activities in Japan as a contrasting location proximal to the Fukushima nuclear power plant that was damaged during the tsunami in 2011. In Europe we find that 137Cs anomalies show up in moose, mushrooms and ground radiation levels in specific years that differ from place to place. There is little indication of direct relationships between weather conditions and 137Cs anomalies. However, environmental processes play critical roles in radionuclide behavior and may themselves be influenced by weather conditions and furthermore by changing climate. Erosion likely remobilizes subsurface 137Cs and transports it downstream where it may be deposited. Erosion is driven by heavy rainfall, snowmelt, and daily variations in temperature that alternatively freeze and thaw the ground. These insights have helped us interpret signs of erosion and deposition of soil contaminated with 137Cs in our case-study areas. Future variations in temperature, precipitation and extreme weather events will likely increase the occurrence of erosion and hence the redistribution of 137Cs in the environment. We have identified several areas sensitive to accumulation of and hence contamination by 137Cs in Europe. In most places the levels of 137Cs accumulation are rarely hazardous, however we recommend that local authorities assess the risks of new construction sites, agricultural practices and free-time activities such as hunting game and gathering mushrooms in areas that are sensitive to 137Cs accumulation.