Las Vegas/Grand Canyon weather in March?

Grand Canyon/Havasu Falls: Expect cold weather. Spring's in April, and temps rise, but no earlier. Havasu Falls requires a min. 6 to 8 hour hike. If you do this, book your beds at The Lodge ASAP or you will have to pitch a tent. Hotel rooms are limited. You'll get great video at the South Rim of the Grand Canyon. West Rim, which is closer to Vegas, will be warmer, but don't expect a huge difference.