There appears to have been a warming until the early 1940's then a moderate cooling until the mid 1970's, followed by a renewed and pronounced warming continuing through the present. The 1990's was the warmest decade on record. Night-time temperatures over land have generally increased more than daytime temperatures.
Regional changes are also evident.
For example, recent warming has been greatest over the mid-latitude continents in winter and spring, with a few areas of cooling such as the North Atlantic Ocean. Precipitation has increased over land in high latitudes of the Northern Hemisphere, especially during the cold season. This is consistent with predictions of climate change due to an enhanced greenhouse effect and increased aerosols. Yet, it could also be within acceptable limits for natural temperature variation. However this warming has not been consistent throughout the entire time span.