The common words temperature and February are often pronounced with vowel elision and/or dejotation, by which latter is meant here the elision of a liquid or glide following a consonant and preceding the medial vowel, resulting in phonetic variation, viz. [témpəchur] and [fébyueri], alongside the pronunciations that are guided by orthography. In the case of February the dropping of r after b does not alter the fact that the glide (transcribed by the letter y here) remains regardless of which variant is heard in contemporary (American) English.
Someone unfamiliar with the arcana of structural linguistics may wonder why such an elision takes place despite the orthography. The reason lies in the nature of the relation between speech sounds and their implementation. Every speech sound has a content that is manifested in actual utterances in such a way as to reveal––to both learner and user––just what that content is. In semiotic terms, this is to say that there is an iconic relation between the sounds and the rules of their implementation. The rules of a language’s phonology are a map of its distinctive features. In other words, the rules of combination of linguistic units (here: sounds) are a function of the units’ makeup.
In the case of the two words at issue, one needs also to realize that speech sounds do not occur in isolation but are grouped together in syllables, which are the basic gestalt domains of speech. A syllable is defined by three POSITIONS : the nucleus––usually a vowel––and two margins, namely the onset and the coda, which are resp. the initial and the final sounds in the syllable, preceding and following the vocalic nucleus. Taking a monosyllable like sprat as a handy example, the onset consists of spr- and the coda of t.
Returning to temperature and February, in each case there is an extant pronunciation that is at variance with the orthography whereby the liquid r in onset position following an obstruent (= true consonant) is elided before the vowel. The sound change that is constituted by this elision falls under the compass of a general process called DEJOTATION, defined as the dropping of a liquid or glide in onset position. The function of such changes is to produce an icon of the relation between UNIT and CONTEXT, here between sound and syllable. It is through processes of this kind that all languages remain true to their nature as structures (patterns) and are not merely agglomerations of facts. This is, indeed, the logic governing all linguistic variation.