Я вложил данные Json, хранящиеся в переменных, как мне получить к ним доступ в другой функции в jquery?

Просто объявите его вне функции, и вы сможете использовать эту переменную в своих main_info и secondary_info т.е.

var city;
var state;
var timeZone;
var contactPhone;
var contactEmail;
var contactName;
var address1;
var address2;
var postalCode;

//hosts
var host;
var specialGuest;
var cohost;


//tiers
var tierTitle;
var tierDecription;
var tierPrice;
var tierRaiser;
var tierMax;
var tierQuantity;

var shiftStart;
var shiftEnd;       //getting all nested records


evt.locations.forEach(function(locations, i, array) {
    //location data
    city= evt.locations[i].city;
    state= evt.locations[i].state;
    timeZone= evt.locations[i].timezone;
    contactPhone= evt.locations[i].contactPhone;
    contactEmail= evt.locations[i].contactEmail;
    contactName= evt.locations[i].contactName;
    address1= evt.locations[i].address1;
    address2= evt.locations[i].address2;
    postalCode= evt.locations[i].postalCode;

    //hosts
    host= evt.locations[i].tags.host;
    specialGuest=evt.locations[i].tags.specialGuest;
    cohost=evt.locations[i].tags.cohost;


    //tiers
    tierTitle= evt.locations[i].tiers[i].title;
    tierDecription= evt.locations[i].tiers[i].decription;
    tierPrice=evt.locations[i].tiers[i].price;
    tierRaiser=evt.locations[i].tiers[i].raiser;
    tierMax=evt.locations[i].tiers[i].maxNum;
    tierQuantity=evt.locations[i].tiers[i].quantity;

    shiftStart= evt.locations[i].shifts[i].startDate;
    shiftEnd= evt.locations[i].shifts[i].endDate;

    console.log(evt.locations[i].city)

});

Пытаться:

$(document).ready(function(){
// Getting all the data from AWS link
    $.ajax(
    {
        url: 'https://s3.amazonaws.com/interview-api-samples/events-results.json',
        cache: false,
        dataType: 'json',
        type: 'GET',
        data: ({ 'events' : [] }),
        success: hillEvents,
        error: function(e, xhr)
        {
            console.log(e);
        }

    });

    function hillEvents(data)
    {
        $('#hillEvents').html(data.Date);
        $.each(data.events, function(i, evt){

            // converting date and time.

            var eventStart= evt.startDate;
            var myDate = new Date(eventStart);

            // changing myDate to a date string
            var dateString = 
              myDate.getUTCMonth() +"/"+
              ("0" + (myDate.getUTCDate()+1)).slice(-2) +"/"+
              ("0" + myDate.getUTCFullYear()).slice(-2);


            // Converting time from military to standaerd and checking if it is am/pm
            var hours = myDate.getUTCHours();
            var minutes =myDate.getUTCMinutes();

            var timeOfEvent = "" + ((hours >12) ? hours - 12 : hours);
                timeOfEvent += (minutes < 10) ? ":0" + minutes : ":" + minutes;
                timeOfEvent += (hours >= 12) ? " P.M." : " A.M.";



        //getting all nested records


            $.each(evt.locations,function(i,locations) {

                //location data
                var city= locations.city;
                var state= locations.state;
                var timeZone= locations.timezone;
                var contactPhone= locations.contactPhone;
                var contactEmail= locations.contactEmail;
                var contactName= locations.contactName;
                var address1= locations.address1;
                var address2= locations.address2;
                var postalCode= locations.postalCode;

                //hosts
                var host= locations.tags.host;
                var specialGuest=locations.tags.specialGuest;
                var cohost=locations.tags.cohost;


                $.each(locations.tiers,function(i,v){
                var tierTitle= v.title;
                var tierDecription= v.decription;
                var tierPrice=locations.price;
                var tierRaiser=v.raiser;
                var tierMax=v.maxNum;
                var tierQuantity=v.quantity;
                 });
              $.each(locations.shifts,function(i,v){
                var shiftStart= v.startDate;
                var shiftEnd= v.endDate;
                           });





            });


            var main_info ='<h1>' + evt.name + '</h1>';
            main_info += '<p>' +  evt.templateInfo.title + '</p>';
            main_info += '<p>' + evt.description + '</p>';
            main_info += '<p> Date: ' + dateString + " "+ timeOfEvent+ '</p>';
            main_info += '<button class="eventsButton">View Event Details</button>';


            // only counts first record
            // main_info += '<p class="mainInfo">' + locations.city + ','+ locations.state +'</p>';



            var secondary_info = '<h1 class="">' + 'hello'+ '</h1>';
            secondary_info += '<p class="">' + evt.description + '</p>';
            secondary_info += '<p class="">' + evt.createdDate + '</p>';
            secondary_info += '<p class="">' + evt.createdDate + '</p>';
            secondary_info += '<p class="">' + evt.guestsCanInviteOthers + '</p>';
                $("div.content").append("<div class=event><div class=main_info>"+ main_info +"<div class='secondary_info>'"+ secondary_info +"<input class=attending type=checkbox>"+"I will attend this event"+"</>"+"</div></div></div>");


        });

    }

    console.log("done");

});