Planning for the weather is a good way to make your trip to Butterworth relaxing and enjoyable, especially when you’re splurging. The hottest months are usually March and May, with an average temperature of 28°C, while the coldest months are January and February, with an average of 27°C. The rainiest months in Butterworth are November, October, December and May, with each month seeing an average of 316 mm of rainfall.