Intra-annual growth patterns of Racomitrium lanuginosum, Pleurozium schreberi, Sphagnum austinii, Sphagnum fuscum, Sphagnum rubellum, Sphagnum papillosum, Sphagnum lindbergii, Sphagnum tenellum, and Sphagnum pacificum were studied in relation to local precipitation and temperature in a sloping open peatland on the hypermaritime north coast of British Columbia. The growth of mosses was strongly correlated with precipitation and less with temperature. A temperature effect on growth was suggested by the emphasized correlation between growth and a combination of precipitation and temperature. Temperature thresholds for Sphagnum spp. were estimated to be lower than those for P. schreberi and R. lanuginosum. Growth rates of hummock Sphagnum spp. were lower and the seasonal growth pattern was less variable than those of hollow and lawn Sphagnum spp. Despite low vertical growth rates, hummock Sphagnum spp. had higher productivity than hollow and lawn Sphagnum spp. Winter-growth in this hypermaritime region appears to be important.