Cemetery and crematorium bosses say they missed their budget target by £50,000 in the last financial year due to a fall in the number of deaths.
Cheltenham Borough Council overshot its expected spending last year after fewer people than expected died in February.
The Bouncers Lane facility dealt with 45 fewer cremations in February than the authority had budgeted for.
Bereavement services manager Rob Hainsworth said: "The nub of the matter is that the council estimates income from burials and cremations as best they can, based on figures from previous years.
"These figures are then revised in October using the half yearly returns.
"However, we have no way of knowing how many people will die in any one month and require the use the council's burial and cremation services.
"Winter months tend to see higher death rates than the summer, but for reasons unknown to the council February this year was quieter than anticipated."
The shortfall in deaths during the second month accounted for about £25,000 in lost income.
Between 13 and 15 fewer people elected to take up a spot in the cemetery in the year to April, leaving a £15,000 gap in budgets.
The council usually carries out 1,926 cremations and 262 burials each year. It charges £555 for a cremation or £1,022 for a 50-year lease on a single grave, or £1,097 for a double plot, with a £135 fee for use of the chapel.
Susanna Morran, partner at actuary firm Barnett Waddingham, said: "Councils may be expecting a certain number of deaths every month, but that number may not occur.
"There are those aspects like poor weather and people living longer that could account for fewer or increased numbers of deaths, but it is difficult to say and they are likely to use past trends to make estimations.
"When looking at a whole year's budget it does seem very specific to say one month has caused them to go over budget."
Actuaries are experts at dealing with the financial risk to companies associated with predicting deaths.
The news was a blow to the council as it tried to balance its books. However, due to savings in other departments it ended the year by recording a £70,000 surplus on its accounts.