Putting It Together
To express the day and complete date, you also need to be able to express the year. This is simpler in Spanish because the year is expressed as a number, not broken up into two, two-digit numbers. Both Spanish and English are comfortable verbally formatting certain years in the same way: 2008 is two thousand eight and dos mil ocho, but in 2010, English speakers are almost certain to return to their verbal habit of splitting the year and saying 20-10. Spanish will continue to express the year as a number: 2,010 or dos mil diez.
Using the date for August 19, 2008 as a model, the question ¿Qué día es hoy? Could be answered simply by saying Hoy es martes, but to express in full the day, date and year one would reply Hoy es martes, el diecinueve de agosto de dos mil ocho. Note the use of el before the number of the day in the month. Finally, please note that ordinal numbers (first, second, third, etc.) are not used to express the date, except for the first of the month, as we shall say in a couple of weeks, e.g., Hoy es lunes, el primero de septiembre de dos mil ocho. The use of de before the year can be replaced by a comma in writing, and a slight pause in speaking.