Describing Current/Past Temperatures
 

When describing the temperature in the present or the past, I'm not sure which verb or conjugation to use.

I want to say:

Last week in Chicago, it was 18 degrees below zero with a windchill of 32 below zero.

Some translators on the internet use está a/estaba a, hace/hacía/había, and es/era when speaking about temperatures, so needless to say, I am totally confused.

What is the best way to translate the above sentence?

My attempt: La semana pasada en Chicago estaba a 18 grados bajo cero con una sensación térmica de 32 bajo cero.


Any rules/guidelines you can give me regarding how to describe the current as well as past temperatures is appreciated.
I don't need help in describing weather conditions or that sort of thing; just temperatures.

Your proposal is fine. http://forums.tomisimo.org/images/smilies/palomita.gif
Also:
- La semana pasada Chicago estaba a menos 18 grados con sensación térmica de menos 32.

You can also use a construction with "nosotros":
- La semana pasada, aquí en Chicago, estábamos/estuvimos a 18 grados bajo cero, con sensación térmica de menos 32.

- Creí que iba a hacer menos frío, porque en la tarde llegamos a los 24 grados, pero dijeron que va a bajar a 7 hoy en la madrugada. :D

In your sentence, "en Chicago estaba", it's understood it's the temperature you're talking about.
In "Chicago estaba", it's the temperature of the city.
And in "estábamos"/"llegamos" it's the temperature at which we're living. :)

All of those ways to express temperature are commonly used, I don't think there is any better than the others. :)

Thank you, AngelicaDeAlquezar. That's what I needed to have clarified when speaking about temperatures.