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Canada crude - Synthetic rises to four-month high

* Feb synthetic trades at $2.50/bbl above WTI

* Feb WCS trades at $20.00/bbl below WTI

CALGARY, Alberta, Jan 3 (Reuters) - Light synthetic crude from the oil sands climbed to a four-month high on Friday, as some traders bet that harsh weather in northern Alberta could hurt supply.

Syncrude's oil sands operations in northern Alberta produced an average of 291,300 barrels per day in December, 10 percent less than the previous month, according to Canadian Oil Sands Ltd, the project's largest-interest owner.

Light synthetic crude from the oil sands for February delivery rose to $2.50 per barrel above the West Texas Intermediate benchmark, according to Shorcan Energy brokers.

That was the highest premium since late August and compares with a settlement price of $1.60 per barrel above WTI on Thursday.

Temperatures in the oil sands hub of Fort McMurray have fluctuated between -38 degrees C and -5 C since Wednesday and are forecast to fall back to around -30 C over the weekend. Market players in Calgary said those sharp swings could cause problems with production.

Concerns about potential supply risks helped offset the impact of reduced demand from the 130,000 bpd Co-op refinery in Regina, Saskatchewan.

The refinery, which runs on a mixture of heavy and synthetic crude, is operating at about half capacity after an explosion rocked the facility last week. By mid-January it is expected to be processing 90,000 bpd.

West Canada Select heavy blend for February delivery last traded at $20.00 per barrel below WTI, little changed from Thursday when it settled at $19.75 per barrel below the benchmark.

Suncor Energy Inc, Canada's largest energy company, also reported December production numbers on Friday.

Output from oil sands operations averaged 417,000 bpd for the month, down 4.6 percent from the 437,000 bpd produced in November but above the year-to-date average of 361,000 bpd.