if else complications in C

In my code I trying to build this weather calculator for class. I am having issues with these if else statements and I can't seem to figure out why any extra eyes please take a look. The if's are supposed to print out separate statements based on the average temp however, it always outputs the second statement.

#include <stdio.h>

int main(void){
    int high_temp[14];
    int warmdays = 0, colddays = 0, i = 0;
    float average = 0.0f, sum = 0.0f;


    printf("\nWeather Analyzer Application by Joey Peters");
    for(i = 0; i < 14; i++) {
        printf("\n\nPlease enter the temperature for day #%d ", i+1);
        scanf("%d", &high_temp[i]);

        sum += high_temp[i];

        if(high_temp[i] > 60){
            warmdays++;
        }

        if(high_temp[i] < 60){
            colddays++;
        }


    }

        average = sum / 14;
        printf("\nThe number of warm days: %d", warmdays);
        printf("\nThe nuber of cold days: %d", colddays);
        printf("\nThe average high temperature: %.2f", average);

        if(average = 100 || average >= 90 ){
            printf("These two weeks were blazing hot");
        }
    else    
        if(average >= 80 || average <= 89){
            printf("\nThese two weeks were quite hot");
        }
    else    

        if(average >= 70 || average <= 79){
            printf("\nThese two weeks hot for Michigan");
        }
    else    

        if(average >= 60 || average <= 69){
            printf("\nThese two weeks were decent for Michigan");
        }
    else    
        if(average >= 50 || average <= 59){
            printf("\nThese two weeks were somewhat cold");
        }
    else
        if(average < 50){
            printf("\nThese two weeks were basically cold");
        }   

    printf("\n\nThank you for using the weather analyzer!");
    return 0;

}