1) April forecast 2) Bad for picnicking 3) Befitting of umbrellas 4) Bucketing 5) Canada-US river 6) Causing a postponement 7) Changeable 8) Coming down outside 9) Day many save for 10) Day to be saved up for 11) Day to save for 12) Drizzling 13) Drizzly 14) Fit for ducks 15) Forecast word 16) Hardly fair Found on https://www.crosswordclues.com/clue/rainy
Rain'y (-ȳ) adjective [ Anglo-Saxon regenig .] Abounding with rain; wet; showery; as, rainy weather; a rainy day or season. Found on http://www.encyclo.co.uk/webster/R/6