The choice is not between "has" and "had."
The choice is between "has" and "have."
"Had" is just plain wrong, so you can stop worrying about that.
The question is: Do you consider the subject of the sentence to be a plural: "They have always been my favorite type of weather."
In fact, the subject is plural ("Snowfall and cold weather have always been my favorite type of weather."), so you should use "have."
However, the sentence is not remarkable for its felicity:
- It repeats the word "weather"
- what is "cold weather in general"? Is it different from "cold weather"?
- The plural subject is an uneasy match with "type"
- It's a passive-sounding construction
- What is "a type of weather"? Is it different from "weather"?
I think you should just rephrase the sentence to say:
I love cold weather and snow.
If this is too stark, add a supporting detail or two:
"One of the greatest gifts I ever got was my 48" Flexible Flyer."
Amazon.com: Flexible Flyer 48" Flexible Flyer Sled: Sports & Outdoors