The city generally has a climate with warm days followed by cool nights and mornings. Unpredictable weather is expected, given that temperatures can drop to 1 °C (34 °F) or less during the winter. During a 2013 cold front, the winter temperatures of Kathmandu dropped to −4 °C (25 °F), and the lowest temperature was recorded on January 10, 2013, at −9.2 °C (15.4 °F). Rainfall is mostly monsoon-based (about 65% of the total concentrated during the monsoon months of June to August), and decreases substantially (100 to 200 cm (39 to 79 in)) from eastern Nepal to western Nepal. Rainfall has been recorded at about 1,400 millimetres (55.1 in) for the Kathmandu valley, and averages 1,407 millimetres (55.4 in) for the city of Kathmandu. On average humidity is 75%. The chart below is based on data from the Nepal Bureau of Standards & Meteorology, "Weather Meteorology" for 2005. The chart provides minimum and maximum temperatures during each month. The annual amount of precipitation was 1,124 millimetres (44.3 in) for 2005, as per monthly data included in the table above. The decade of 2000-2010 saw highly variable and unprecedented precipitation anomalies in Kathmandu. This was mostly due to the annual variation of the southwest monsoon.[citation needed] For example, 2003 was the wettest year ever in Kathmandu, totalling over 2,900 mm (114 in) of precipitation due to an exceptionally strong monsoon season. In contrast, 2001 recorded only 356 mm (14 in) of precipitation due to an extraordinarily weak monsoon season.