The phrase "weather dice" refers to the unpredictable nature of the weather. It means that the weather can change randomly, just like rolling dice. Full definition
So, in effect, we need to find out if we are getting «too many double - sixes» with the British weather dice. (climateprediction.net)
Otto said: «Past greenhouse gas emission and other forms of pollution have loaded the weather dice», adding that she and others were still working on investigating the implications of the results, for river flows, flooding and ultimately the threat to property and lives. (scientificamerican.com)
Otto said greenhouse gas emissions have «loaded the weather dice», so the probability of extremely wet winters has slightly increased. (carbonbrief.org)