Planning for the weather is a good way to make your trip to Arthur’s Pass relaxing and enjoyable, especially when you’re splurging. The hottest months are usually February and January, with an average temperature of 10°C, while the coldest months are July and August, with an average of 0°C. The rainiest months in Arthur’s Pass are May, September, October and July, with each month seeing an average of 281 mm of rainfall.