abstract: The paper presents the results of 16 years (1983-1999) of investigations on the effect of mean and extreme temperatures, relative humidity and sum of precipitations on duration of phenological periods on twin feathered pea cultivars (variety: Karat and Rubin). The investigated data were obtained from three cultivar testing stations (Karżniczka, Radostowo and Chrząstowo) located in north-central part of Poland. The experiments were conducted precisely according to COBORU method; among other things annual data of sowing and basic phenological periods. Duration of the periods of pea cultivars was calculated: sowing-germination, germination-beginning of flowering-end of flowering, end of flowering-technical maturity. The meteorological factors which impacted the strongest on the duration of phenological periods were described according to regression equations. The equations were verified using the determination coefficient. It was found that the meteorological factors had a significant effect on phenological periods which depended on varieties of plants and growth period. The duration of initial growth periods depended on mean values of maximum temperatures (sowing-germination, germination-beginning of flowering) or their sum (flowering period), but the duration of the end of flowering period-technical maturity was influenced by mean and minimum sum of temperatures.