Spring: Yellowstone Reborn
Spring is a colorful season when Yellowstone is reborn! Receding white snow and emerging green plant life highlight the season when bald eagles nest, baby buffalo are born, bull elk are in the velvet, young wolves emerge from their dens, and both black and grizzly bears can be seen throughout the Park.
The weather can be unpredictable and range from warm sunshine to heavy snow (often in the same day), but that is offset by the un-crowded roads and boardwalks and lower hotel rates.
SeeYellowstone tours of both the Lower & Upper Loops as well as the Grand Tetons start (Weather Permitting) on Mothers day (USA) weekend.
More details on the tours can be found on the SeeYellowstone website.