Note the time of year of the death and the time of year of the burial. In New England, I've seen several obituaries from winter deaths that say someone will be buried later in the spring.
In the post The Frozen Chosen: Winter Grave Digging Meets Modern Times, Traci Rylands says:
Before the invention of the backhoe, there was only one way to dig a
grave and that was with a shovel. It could take quite a lot of
backbone and energy to accomplish even in warmer conditions. But when
the ground froze, it could be nearly impossible.
Often, families simply waited until spring to bury their loved ones.
The dead would be placed in what was called a receiving vault, where
they might wait a few weeks to a few months for burial.
The post shows several modern devices that can thaw the soil enough for burials to take place. If a cemetery is a small family cemetery, they may not have the equipment to thaw the soil enough for burial.
Check state law for your location to see whether winter burials are mandated (Minnesota and Wisconsin, according to the linked blog post) or whether burials can be suspended until the spring (e.g. North Dakota).
North Dakota funeral directors say a law requiring them to have winter burials would be impractical if not impossible for the hundreds of small rural cemeteries scattered across the sparsely populated state. Just plowing the country road to get to the cemetery can be an arduous task.
Perhaps this isn't obvious, but if no one can get to the cemetery in winter because of impassable country roads, holding a graveside service isn't practical. Spring graveside services for people who died in winter may be delayed even more because they may have to be scheduled around the services for people who died in the spring.