Annual, seasonal and semiannual variations of F2-layer electron density (<i>N</i>mF2) and height (<i>h</i>mF2) have been compared with the coupled thermosphere-ionosphere-plasmasphere computational model (CTIP), for geomagnetically quiet conditions. Compared with results from ionosonde data from midlatitudes, CTIP reproduces quite well many observed features of <i>N</i>mF2, such as the dominant winter maxima at high midlatitudes in longitude sectors near the magnetic poles, the equinox maxima in sectors remote from the magnetic poles and at lower latitudes generally, and the form of the month-to-month variations at latitudes between about 60°N and 50°S. CTIP also reproduces the seasonal behaviour of <i>N</i>mF2 at midnight and the summer-winter changes of <i>h</i>mF2. Some features of the F2-layer, not reproduced by the present version of CTIP, are attributed to processes not included in the modelling. Examples are the increased prevalence of the winter maxima of noon <i>N</i>mF2 at higher solar activity, which may be a consequence of the increase of F2-layer loss rate in summer by vibrationally excited molecular nitrogen, and the semiannual variation in <i>h</i>mF2, which may be due to tidal effects. An unexpected feature of the computed distributions of <i>N</i>mF2 is an east-west hemisphere difference, which seems to be linked to the geomagnetic field configuration. Physical discussion is reserved to the companion paper by Rishbeth <i>et al</i>.<br><br><b>Key words: </b>Atmospheric composition and structure (thermosphere-composition and chemistry) - Ionosphere (mid-latitude ionosphere; modelling and forecasting)