Planning for the weather is a good way to make your trip to Monrovia relaxing and enjoyable, especially when you're splurging. The hottest months are usually January and April, with an average temperature of 27°C, while the coldest months are August and September, with an average of 25°C. The rainiest months in Monrovia are September, June, August and July, with each month seeing an average of 608 mm of rainfall.