* Within-day gas down 1.75 pence at 31.00 p/therm by 0902 GMT
* Day-ahead gas up 1.25 pence to 31.25 pence/therm
* Within-day gas price in Britain reached very high levels last week and traded lower on Monday.
* The day-ahead price, however, followed oil with temperatures are expected to fall in Britain on Tuesday, traders added.
* Oil prices surged on Monday, with Brent crude posting its biggest intra-day percentage gain since the Gulf War in 1991, after an attack on Saudi Arabian oil facilities on Saturday shut more than 5% of global supply.
* Average daily temperatures are forecast at 14.7 degrees Celsius for Monday and are expected to fall to 12.6C the next day, Refinitiv Eikon data showed.
* The British gas system was slightly undersupplied, with demand forecast at 169.4 million cubic metres (mcm) and supply at 167.6 mcm/day, National Grid data showed.
* Norwegian gas flows to Britain are at low levels, flat at 22 mcm/day. Gas flows via the largest pipeline between the two countries, Langeled, remain halted due to maintenance. Flows via Vesterled were also low at 5 mcm/day.
* Wind power generation is expected to reach 4.6 gigawatts (GW) on Monday out of 12.1 GW capacity, according to Elexon data. It is forecast at 4.4 GW on Tuesday.
* The October gas contract fell by 0.08 pence to 38.70 pence per therm.
* Day-ahead gas at the Dutch TTF hub rose by 0.73 euro to 11.30 euros per megawatt hour (MWh)
* The Dutch month-ahead gas contract, a benchmark for LNG prices as well as European gas, was up by 0.35 euro at 14.75 euros/MWh.
* The benchmark Dec-19 EU carbon contract rose by 0.20 euros to 26.58 euros a tonne