I know my dictionary has values.

func loopthroughDic() { // DELETE
        weatherDictionary.forEach { print($0) }
    }

(key: "Tuesday", value: "Clear")
(key: "Thursday", value: "Rain")
(key: "Saturday", value: "Clear")
(key: "Wednesday", value: "Clouds")
(key: "Sunday", value: "Clear")
(key: "Friday", value: "Rain")
(key: "Monday", value: "Clouds")

Function that doesn't work. I am just sending "Monday" to it right now. Text("(WeatherListForcastViewModel.shared.displaySkyInfo(day: "Monday"))")

func displaySkyInfo(day: String) -> String {
        let matchedDay = weatherDictionary.filter { $0.key == day }
        print("Passed Day: \(day)")
        return matchedDay.values.first ?? ""
    }

Passed Day: Monday
Passed Day: Monday
Passed Day: Monday
Passed Day: Monday
Passed Day: Monday
Passed Day: Monday
Passed Day: Monday

Thanks for any assistance.

And the above was based on this playground I created first which does work.

struct Weather {
    let days: [Double]
    let forcasts: [Forcast]
}

struct Forcast {
    let info: [String]
}

var weatherDetails = [Weather]()
weatherDetails.append(Weather(days: [1600362000.0], forcasts: [Forcast(info: ["Clouds"])]))
weatherDetails.append(Weather(days: [1600448400.0], forcasts: [Forcast(info: ["Rainy"])]))
weatherDetails.append(Weather(days: [1600534800.0], forcasts: [Forcast(info: ["Clear"])]))
weatherDetails.append(Weather(days: [1600621200.0], forcasts: [Forcast(info: ["Smoke"])]))
weatherDetails.append(Weather(days: [1600707600.0], forcasts: [Forcast(info: ["Clear"])]))
weatherDetails.append(Weather(days: [1600794000.0], forcasts: [Forcast(info: ["Clear"])]))
weatherDetails.append(Weather(days: [1600880400.0], forcasts: [Forcast(info: ["Smoke"])]))

let actualDays = ["Wednesday", "Thursday", "Friday", "Saturday", "Sunday", "Monday", "Tuesday"]
var xDays = [String]()
var xForcast = [String]()
var xDictionary: [String : String] = [:]

func convertDate(timezone: Int, passedDate: Double) {
    let unixTimestamp = passedDate
    let date = Date(timeIntervalSince1970: unixTimestamp)
    let dateFormatter = DateFormatter()
    dateFormatter.timeZone = TimeZone(abbreviation: "UTC")
    dateFormatter.dateFormat = "EEEE"
    dateFormatter.timeZone = TimeZone(secondsFromGMT: timezone)
    let strDate = dateFormatter.string(from: date)
    xDays.append(strDate)
}

weatherDetails.forEach { (item) in
    convertDate(timezone: -18000, passedDate: item.days[0])
}

weatherDetails.forEach { (item) in
    item.forcasts.forEach { (forcast) in
        xForcast.append(forcast.info[0])
    }
}

for (index, element) in xDays.enumerated() {
    xDictionary[element] = xForcast[index]
}

func getWeatherInfo(day: String) {
    let filtered = xDictionary.filter { $0.key == day }
    let theValue = filtered.values
    print("The Value \(day): \(theValue.first ?? "")")
}

xDictionary.forEach { print($0) }

getWeatherInfo(day: "Friday")

actualDays.forEach { (item) in
    getWeatherInfo(day: item)
}

(key: "Saturday", value: "Clear")
(key: "Wednesday", value: "Smoke")
(key: "Thursday", value: "Clouds")
(key: "Friday", value: "Rainy")
(key: "Monday", value: "Clear")
(key: "Tuesday", value: "Clear")
(key: "Sunday", value: "Smoke")
The Value Friday: Rainy
The Value Wednesday: Smoke
The Value Thursday: Clouds
The Value Friday: Rainy
The Value Saturday: Clear
The Value Sunday: Smoke
The Value Monday: Clear
The Value Tuesday: Clear

You don't need to filter to get the value you need. Dictionary keys are hashable, meaning keys will be unique and you aren't going to have multiple values corresponding to the same key. So you can just do return weatherDictionary[day] to get the value you need.

let weatherDictionary: [String:String] = [
    "Tuesday": "Clear",
    "Thursday": "Rain",
    "Saturday": "Clear",
    "Wednesday": "Clouds",
    "Sunday": "Clear",
    "Friday": "Rain",
    "Monday": "Clouds",
]

func displaySkyInfo(day: String) -> String {
    print("Passed Day: \(day)")
    return weatherDictionary[day] ?? ""
}

let weather = displaySkyInfo(day: "Monday")
print(weather)

//Passed Day: Monday
//Clouds