July 8 (Reuters) - U.S. energy firms likely added a near-normal 49 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 53 bcf during the same week a year ago and an average increase for that week of 51 bcf over the past five years (2021-2025).

In the prior week ended June 26, energy firms added 87 bcf of gas into storage. USOILN=ECI

If correct, the forecast for the week ended July 3 would increase stockpiles to 2.971 trillion cubic feet. That figure would be about 0.9% below the same week a year ago and about 6.2% 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 101 total degree days (TDDs) last week, higher than the 30-year normal of 80 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 nine analysts, whose estimates ranged from injections of 44 bcf to 55 bcf, with a median increase of 49 bcf.

Early estimates for the week ending July 10 ranged from injections of 39 bcf to 55 bcf, with an average increase of 48 bcf.

Those figures compare with an injection of 47 bcf during the same week last year and a five-year average increase of 45 bcf.

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