The diurnal range of temperature in Polar Regions is, as a matter of rule, always smaller because places near the poles experience the same low angle of incidence of the sun’s rays throughout the day.
Along the sea coasts the daily air temperature curve does not exhibit solar control. The daily temperature rhythm is modified by the land and sea breezes. Similarly, a place located on a windward coast is likely to experience a smaller diurnal range of temperature.
On the contrary, locations far inland have a higher daily temperature range. In other words, stations having a strong oceanic influence have smaller daily temperature ranges than stations located far from the influence of water.
The diurnal range is much larger on land than at sea. The temperature curve depends on the season as well as the weather.