In terms of precipitation, rainfall in Iliamna ranges from 0.8 - 4.6 inches per month. September is typically the wettest month, when rainfall can reach 4.6 in. March is typically the driest time to visit Iliamna when rainfall is around 0.8 in.
If weather is an important factor for your trip to Iliamna, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 55.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 17.6 F).