Magny, M., Peyron, O., Gauthier, E., Vanniere, B., Millet, L. and Vermot-Desroches, B. 2011. Quantitative estimates of temperature and precipitation changes over the last millennium from pollen and lake-level data at Lake Joux, Swiss Jura Mountains. Quaternary Research 75: 45-54.
Working at Lake Joux (46°36'N, 6°15'E) in the Swiss Jura Mountains, Magny et al. employed a multi-proxy approach with pollen and lake-level data to develop a 1000-year history of the mean temperature of the warmest month of the year (MTWA), which was July at Lake Joux, based on the Modern Analogue Technique. This work revealed what they describe as an "MWP between ca. AD 1100 and 1320," during which time the MTWA at Joux Lake exceeded that of the 1961-1990 reference period by fully 2.0°C. They also note there was an increase in the MTWA of about 1.6°C at nearby Laoura for the period 1991-2008, when compared to the reference period 1961-1990; and they report that meteorological data observed at nearby La Brevine suggest a similar pattern with an increase in MTWA by 1°C over the period 1991-2008 relative to 1961-1990. Thus, it would appear that the peak warmth of the MWP at Lake Joux exceeded that of the CWP at that location by something on the order of 0.4-1.0°C.