React component with weather-widget

weather.jsx

/* Import variables ***************************************************************************************************/
import React from 'react';
import ReactDOM from 'react-dom';

/* React components ***************************************************************************************************/
export default class Weather extends React.Component{
    constructor(props) {
        super(props);
        this.state = {
            city: ``,
            temp: ``,
            icon: ``,
            description: ``
        };
    }

    componentWillMount() {
        let XHR = (`onload` in new XMLHttpRequest()) ? XMLHttpRequest : XDomainRequest; //to support IE8
        let ipXhr = new XHR(),
            weatherXhr = new XHR(),
            THIS = this;

        ipXhr.open(`GET`, `https://weathersync.herokuapp.com/ip`, true);
        ipXhr.send();

        ipXhr.onreadystatechange = function () {
            let lat = ``,
                lng = ``;

            if (ipXhr.readyState != 4) return;
            if (ipXhr.status != 200) {
                console.log(`error ${ipXhr.status}: ${ipXhr.statusText}`);
            } else {
                let ip = JSON.parse(ipXhr.responseText);
                lat = ip.location.latitude;
                lng = ip.location.longitude;

                weatherXhr.open(`GET`, `https://weathersync.herokuapp.com/weather/${lat},${lng}`, true);
                weatherXhr.send();
                weatherXhr.onreadystatechange = function () {
                    if (weatherXhr.readyState != 4) return;
                    if (weatherXhr.status != 200) {
                        console.log(`error ${weatherXhr.status}: ${weatherXhr.statusText}`);
                    } else {
                        let obj = JSON.parse(weatherXhr.responseText),
                            city = obj.name,
                            temp = Math.floor(1.8 * (obj.main.temp - 273) + 32), //Convert Kelvin to Fahrenheit
                            icon = `http://openweathermap.org/img/w/${obj.weather[0].icon}.png`,
                            description = obj.weather[0].description;

                        THIS.setState({city: city});
                        THIS.setState({temp: `${temp} ºF`});
                        THIS.setState({icon: icon});
                        THIS.setState({description: description});
                    }
                }
            }
        };
    }
    
    render() {
        return (
            <div>
                <h1>{this.state.city}</h1>
                <p>{this.state.temp}</p>
                <img src={this.state.icon}/>
                <h2>{this.state.description}</h2>
            </div>
        )
    }
}