* Injection estimates ranged from 25 bcf to 51 bcf
* Median build in the Reuters poll was also 35 bcf (Adds weather data, background, table)
NEW YORK, July 28 (Reuters) - U.S. natural gas storage levels on average are expected to rise by 35 billion cubic feet when weekly data from the U.S. Energy Information Administration are released early Thursday.
In the weekly Reuters survey of 27 industry traders and analysts, injection estimates for the week ended July 23 ranged widely from 25 bcf to 51 bcf.
Stocks rose an adjusted 70 bcf for the same week last year, while the five-year average gain for that week is 50 bcf.
The median build in the survey was also 35 bcf.
The EIA storage report will be issued Thursday at 10:30 a.m. EDT (1430 GMT).
Those on the low side of estimates noted hot weather last week again slowed injections, while strong cash premiums to NYMEX futures and a flatter forward curve offered less incentive for economic storage players to build up stocks.
The U.S. National Oceanic and Atmospheric Administration said there were 97 cooling degree days last week, four warmer than the previous week, 22 warmer than normal and 34 warmer than the same week last year.
Degree days, a measure of departure in the mean daily temperature from 65 degrees Fahrenheit (18 Celsius), are used to reflect demand for energy to cool or heat homes and businesses.
In the last report for the week ended July 16, overall storage rose 51 bcf, just shy of the Reuters survey estimate of 53 bcf and below the year-ago gain of 70 bcf and the five-year average increase for that week of 64 bcf.
The report showed total domestic gas inventories climbed to 2.891 trillion cubic feet, 52 bcf, or 2 percent, below last year's record high but a level not normally reached until the third week of August.
The weekly build cut the inventory surplus to the five-year average by 13 bcf to 261 bcf, but storage still stands at a comfortable 10 percent cushion to that benchmark.
Eastern storage climbed 41 bcf in the last report but slipped to about 2 percent below last year's levels.
Consuming Region West storage, which gained 4 bcf for the week, edged up to 7 percent above the same year-ago week.
Inventories in the Producing Region added 6 bcf but fell to 5 percent below the same week in 2009.
A total build Thursday at the Reuters survey estimate would widen the deficit to last year to 87 bcf and trim the surplus to the five-year average to about 246 bcf.
In the last four reports, total stocks rose 267 bcf, or about 67 bcf per week, versus a 305-bcf adjusted increase for the same one-month period last year and a 315-bcf five-year average gain for that period.
NOAA said it expected 89 cooling degree days this week, 14 warmer than normal and 14 more than the same year-ago week.
Early injection estimates for next week's EIA report range from 25 bcf to 48 bcf, versus a 67 bcf build for the same week last year and a five-year average gain of 47 bcf.
Storage hit an all-time high of 3.837 tcf in late November, and ended March with about 1.65 tcf in the ground, or about 11 percent above the five-year average at the start of the April-through-October stock building season.
If weekly stock builds through October match the five-year average pace, U.S. inventories will begin next heating season with 3.744 tcf in the ground, below last November's record high of 3.837 tcf, but still about 7 percent above average.
To get inventories above last year's record high of 3.837 tcf by Nov. 1, weekly injections must average 63 bcf for the remaining 15 weeks of the stock building season, well above the five-year average of 57 bcf for that period.