Other facts from our historical weather data: When is summer in Oakley?The hottest season / summer takes place in June, July, August and September. Does Oakley have a dry season? Yes, the months of January, February and November are very dry. Which is the warmest month in Oakley? July has an average maximum temperature of 33°C (91°F) and is the warmest month of the year. Which is the coldest month in Oakley? The coldest month is January with an average maximum temperature of 6°C (43°F). Which is the wettest month in Oakley? May tops the wettest month list with 83mm (3.3 in) of rainfall. Which is the driest month in Oakley? January is the driest month with 7mm (0.3 in) of precipitation. 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.