Glaciers were smaller than today
Also the global retreat of glaciers that occurred in the period between about 900 to 1300  speaks for the existence of the Medieval Warm Period. An interesting detail is that many glaciers pulling back since 1850 reveal plant remnants from the Middle Ages, which is a clear proof that the extent of the glaciers at that time was lower than today .
Furthermore, historical traditions show evidence of unusual warmth at this time. Years around 1180 brought the warmest winter decade ever known. In January 1186/87, the trees were in bloom near Strasbourg. And even earlier you come across a longer heat phase, roughly between 1021 and 1040. The summer of 1130 was so dry that you could wade through the river Rhine. In 1135, the Danube flow was so low that people could cross it on foot. This fact has been exploited to create foundation stones for the bridge in Regensburg this year .
Clear evidence of the warm phase of the Middle Ages can also be found in the limits of crop cultivation. The treeline in the Alps climbed to 2000 meters, higher than current levels are . Winery was possible in Germany at the Rhine and Mosel up to 200 meters above the present limits, in Pomerania, East Prussia, England and southern Scotland, and in southern Norway, therefore, much farther north than is the case today .
On the basis of pollen record there is evidence that during the Middle Ages, right up to Trondheim in Norway, wheat was grown and until nearly the 70th parallel/latitude barley was cultivated. In many parts of the UK arable land reached heights that were never reached again later.
Also in Asia historical sources report that the margin of cultivation of citrus fruits was never as far north as in the 13th century. Accordingly, it must have been warmer at the time about 1 ° C than today .