Within-day gas price was up 0.50 pence at 29.85 p/therm at 0800 GMT.

The June contract inched up by 0.05 pence to 30.25 p/therm.

Cooler temperatures are now forecast for next week compared to expectations on Friday, a trader said.

Refinitiv Eikon data shows the average daily temperature forecast across the next 15 days is 0.4 degree Celsius lower than previously forecast.

The average daily temperatures forecast for Tuesday has been lowered by 2.7 degrees Celsius to 11.5 degrees.

Another trader added that as Monday was a holiday in Britain, trade is quite slow and prices could shift direction later in the day.

On the supply side, send-out from British terminals has dipped slightly to 60 million cubic metres (mcm) per day compared to 66 mcm the previous day.

Storage injections are nominated at 18 mcm/day.

However, gas flows via the Langeled pipeline from Norway rose by 27 million cubic metres (mcm) to 40 mcm after a significant reduction on Friday.

"These flows were most likely offline due to commercial reasons," Refinitiv Eikon gas analysts said in a note.

The system is largely balanced with demand forecast at 226.7 million cubic metres (mcm) and supply at 225.7 mcm a day, National Grid data shows.

Peak wind generation is forecast at around 3.2 gigawatts (GW) on Tuesday out of a total metered capacity of around 12 GW but that is expected to rise to 6.3 GW on Wednesday, Elexon data shows.

Day-ahead gas price at the Dutch TTF hub inched up by 0.02 euro to 12.32 euros per megawatt hour

Benchmark Dec-19 EU carbon contract fell by 0.26 euro to 25.33 euros a tonne.