Planning for the weather is an important factor for making your trip to Isny im Allgaeu a success, especially when you’re splurging. The hottest months are usually July and August, with an average temperature of 16°C, while the coldest months are January and February, with an average of 0°C. The rainiest months in Isny im Allgaeu are August, May, June and July, with each month seeing an average of 186 mm of rainfall.