Table 2.

Air temperature, humidity and light conditions in the year 2005 (mean±s.d.).

month	temperature (°C)	humidity (%)	radiation (MJ m−2)
January	−12.8±0.1	61±0.4	13.2±0.1
February	−9.8±0.1	57±0.6	13.3±0.2
March	−5.1±0.1	67±0.5	15.3±0.2
April	1.0±0.1	58±0.5	20.4±0.1
May	5.0±0.1	73±0.4	22.6±0.1
June	8.7±0.0	78±0.3	22.6±0.0
July	10.9±0.1	80±0.3	20.6±0.1
August	10.4±0.1	81±0.2	19.4±0.1
September	6.7±0.1	82±0.3	15.0±0.0
October	0.1±0.1	69±0.3	14.2±0.1
November	−7.7±0.1	62±0.3	12.9±0.1
December	−13.7±0.1	55±0.3	11.2±0.1