Degrees C. Degrees F.

Very cool 110 - 120 225 - 250
Cool 140 - 150 275 - 300
Moderate 160 - 180 325 - 350
Moderately hot 190 - 200 375 - 400
Hot 220 - 230 425 - 450
Very hot 240 - 250 475 -500

Generally, a warm oven refers to Gas mark 3; a moderate oven, gas mark 4; a fairly hot oven, gas marks 5 - 6; a hot oven, gas mark 7; and a very hot oven is gas marks 8 - 9. (The equivalents in °C and °F can be seen in the table below)

Fahrenheit Celcius Gas Mark
250°F 120°C Gas Mark ½
275°F 135°C Gas Mark 1
300°F 149°C Gas Mark 2
325°F 162°C Gas Mark 3
350°F 176°C Gas Mark 4
375°F 190°C Gas Mark 5
400°F 204°C Gas Mark 6
425°F 218°C Gas Mark 7
450°F 232°C Gas Mark 8
475°F 246°C Gas Mark 9
500°F 260°C Gas Mark 10