Other facts from our historical weather data: Which is the warmest month in Keiss? August has an average maximum temperature of 16°C (61°F) and is the warmest month of the year. Which is the coldest month in Keiss? The coldest month is February with an average maximum temperature of 8°C (46°F). Which is the wettest month in Keiss? October tops the wettest month list with 111mm (4.4 in) of rainfall. Which is the driest month in Keiss? May is the driest month with 63mm (2.5 in) of precipitation. Which is the sunniest month in Keiss? May is the sunniest month with an average of 192 hours of sunshine. No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.