There is a strong space weather need to forecast the daily and hourly variations in ionospheric characteristics that occur within the ionosphere–thermosphere (I–T) system. A number of different models and techniques has been developed for that purpose. Many of these models and techniques can provide a reasonable agreement with the observational data, at least during geomagnetically quiet times. Forecasting ionospheric characteristics during disturbed periods that accompany space weather events is yet more difficult. Examples of two types of relatively simple solutions the space weather community can use in its attempt at short-term (1-h to 24-h in advance) and long-term (few days) ionosphere–thermosphere (I–T) forecasting are given in terms of two important ionosonde characteristics foF2 and MUF(3000)F2.