Global warming has been occurring since the Little Ice Age in the 1600s.  Recently, it appears that 2015 is one of the warmest years for the global average surface temperature.  El Niño occurred in 2015 and contributed to some of the increase in 2015.  The late 1960s was the coolest period in the last half of the 20^th century.    The average global temperature increased 1.0°C (1.8°F) during the period.

First order airport stations are selected from each of the New England states.  The data was processed for 1965 to 2015 and includes minimum and maximum temperature and precipitation.  The daily data was processed and averaged over monthly, seasonal, and annual periods.  Each station was processed independently and regression coefficients were calculated using Excel.   Metadata for each of the sites were examined to determine changes in station locations.  The results for the regression coefficients are shown in the table in °F/decade.

Table:  Regression coefficients in °F/decade for seasonal Minimum and Maximum temperature.

The station with the largest increasing trends is Burlington.  Examination of the time series of temperature show large increases starting in 1973 and in 2008.   A review of the metadata for the station show the station moved 55 feet to a lower elevation in Jan 1973.  A new terminal for the airport opened in Oct 1973.  The terminal was further expanded in 2008.  Substantial suburban homes and the central developed area are to the west of the airport.  These sudden increases were due to the urban heat island effect from the increased activity at the airport and development surrounding the airport.

Bridgeport is located on the shores of Long Island Sound and is heavily influenced by the temperature of water in the Sound.  Temperature data is available for the Sound starting in 1976 and increases 0.6°F per decade.  This accounts for much of the trends at Bridgeport when compared to Hartford and also appears to be an influence on the Providence results.

The results show that the temperatures are summarized as:

• generally increase more rapidly at night than during the daytime in northern New England.
• In southern New England, the temperature rates are nearly the same during the cooler months.
• During the summer, all night temperature trends are increasing more rapidly than during the daytime.
• In general there is little temperature change in the summertime maximum temperature trends with southern New England showing a net cooling over the past 50 years away from Long Island Sound.
• The winter temperatures are rising faster than the global temperature