SUMMARY.1. The literature contains a number of curves relating time (days) required for median hatch (=D2) to water temperature (T,°C) for the eggs of several salmonid fishes. There are relatively few data on the relationships between time to median eyed (= D1), days) or time to median swim‐up (= D3, days) and temperature.2. From published data, over most of the range 0‐9.5°C, approximate relationships are D,=0.5D2for Atlantic salmon (Salmo salar L.) and D3 = 1.7D2for eight species of Salmo and Oncorhynchus.3. Field and hatchery tests suggest that these are useful empirical models for approximate prediction of D1and D3from D2for most salm