Planning for the weather is a good way to make your trip to Haldwani relaxing and enjoyable, especially when you’re splurging. The hottest months are usually May and June, with an average temperature of 28°C, while the coldest months are January and December, with an average of 15°C. The rainiest months in Haldwani are July, August, September and June, with each month seeing an average of 359 mm of rainfall.