You're getting warm if you're looking for ways to say "warm" in Spanish. Look no farther! Warm is a great word whose connotations are all positive. Explore the various ways in which warmth is expressed, from weather to emotions.
Warm: Weather, Emotion, Letters and Social Events
Warmth comes in various shades, so to speak. One may speak of the higher temperature of water as caliente (hot), but if it is only warm, the diminutive comes into play and the word is calentito (warmish). When speaking of food, caliente is only temperature hot, not spicy hot, for which use picante.
Lavó los platos en agua caliente. He washed the dishes in hot water.
Ella bañó el niño en agua calentito. She bathed the boy with warm water.
When speaking of a climate or weather, the word for warm is templado. One way to remember this is to associate it with temperate, a word which in English is used to describe a climate type.
Me mudé a un país con un clima más templado. I moved to a country with a warmer climate.
Turning to the subject of emotions, there are an abundance of terms to use, many of which show up in the closing of letters, in speeches at social events or in articles reporting on them. The Spanish-speaking world uses many of these words in ways that may seem very formal or old fashioned to an English-speaking person from the US, but they are the grease that keeps the politeness of Spanish societies well oiled. It is a good idea to learn these words and learn to use them naturally and automatically.
Me dio un saludo afectuoso. He gave me an affectionate greeting.
English speakers would of course actually say He greeted me affectionately, but it is important to learn both the adjective, as in this example, as well as the adverb afectuosamente: Me saludó afectuosamente.
The synonyms for afectuoso are interchangeable -- that's good news for learners of Spanish. Learn them all so your speech will not be terribly repetitive: cariñoso, caluroso.
The adjectives encarecido, expresivo and vivo are almost always encountered when saying thank you. Note that because the word gracias is feminine and plural, these adjectives have to agree with it in gender and number:
Le ruego que acepte mis más encarecidas gracias. I beg you accept my warmest thanks.
Le di mi más sincero y encarecido agradecimiento. I offered him my sincerest and warmest gratitude.