June 3 (Reuters) - U.S. energy firms likely added a near-normal 101 billion cubic feet of natural gas into storage last week, according to the average estimate in a Reuters poll released on Wednesday.

The estimate compares with an injection of 119 bcf during the same week a year ago and an average increase of 101 bcf over the past five years (2021-2025) for the week.

In the prior week ended May 22, energy firms added 92 bcf of gas into storage. USOILN=ECI

If correct, the forecast for the week ended May 29 would increase stockpiles to 2.584 trillion cubic feet. That figure would be about 5.9% above the same week a year ago and about 0.1% above the five-year average for the week.

The U.S. Energy Information Administration is scheduled to release its weekly storage report at 10:30 a.m. EDT (1430 GMT) on Thursday.

There were 57 total degree days (TDDs) last week, slightly lower than the 30-year normal of 61 TDDs for the period, data from financial firm LSEG showed.

Total degree days measure the number of degrees a day's average temperature is above or below 65 degrees Fahrenheit (18 degrees Celsius) to estimate demand to cool or heat homes and businesses.

Reuters polled 11 analysts, whose estimates ranged from injections of 95 bcf to 115 bcf, with a median increase of 101 bcf.

Early estimates for the week ending June 5 ranged from injections of 85 bcf to 100 bcf, with an average increase of 94 bcf.

Those figures compare with an injection of 110 bcf during the same week last year and a five-year average increase of 95 bcf.

Following is a list of poll participants. All figures are in billion cubic feet: