Hacked first version of weather station code. Bloated, but works.

datalogger.py

import sqlite3
import datetime

sql_live = """SELECT
    strftime('%Y-%m-%d %H:%M GMT', logdate) AS logdate,
    avg({0}) AS {0}
FROM log
WHERE logdate >= datetime('now', '-180 minutes')
GROUP BY strftime('%Y-%m-%d %H:%M', logdate)
ORDER BY 1;"""

sql_pastday = """SELECT
    strftime('%Y-%m-%d %H:%M GMT', min(logdate)) AS logdate,
    avg({0}) AS {0}
FROM log
WHERE logdate >= datetime('now', '-24 hours')
GROUP BY strftime('%Y-%m-%d %H', logdate), strftime('%M', logdate) / 10
ORDER BY 1;"""

sql_pastweek = """SELECT
    strftime('%Y-%m-%d %H:%M GMT', logdate) AS logdate,
    {0}
FROM log_byhour
WHERE logdate >= datetime('now', '-7 days')
ORDER BY 1;"""

sql_pastyear = """SELECT
    strftime('%Y-%m-%d 00:00:00 GMT', logdate) AS logdate,
    avg({0}) AS {0}
FROM log_byhour
GROUP BY strftime('%Y-%m-%d', logdate)
HAVING logdate < date('now')
ORDER BY 1;"""

band_pastyear = """SELECT
    min({0}) AS min,
    max({0}) AS max
FROM log_byhour
GROUP BY strftime('%Y-%m-%d', logdate)
HAVING logdate < date('now')
ORDER BY logdate;"""

sql_update = """INSERT INTO log_byhour
(logdate, temperature, humidity, pressure)
SELECT
    strftime('%Y-%m-%d %H:00:00', logdate) AS logdate,
    avg(temperature) AS temperature,
    avg(humidity) AS humidity,
    avg(pressure) AS pressure
FROM log
WHERE logdate >= ? AND logdate < ?
GROUP BY strftime('%Y-%m-%d %H', logdate)
ORDER BY 1;"""

def log(temperature, humidity, pressure):
    logdate = datetime.datetime.utcnow()
    try:
        con = sqlite3.connect('/var/log/datalog.db')
        with con:
            cur = con.cursor()
            cur.execute('INSERT INTO log (logdate, temperature, humidity, pressure) VALUES(?, ?, ?, ?)', (logdate, temperature, humidity, pressure))
    except Exception, e:
        print '## datalogger.log ## {0}'.format(e)

def getlog(period):
    import json
    data = {}
    if period == 'pastyear':
        sql = sql_pastyear
        band = band_pastyear
    elif period == 'pastweek':
        sql = sql_pastweek
        band = ''
    elif period == 'pastday':
        sql = sql_pastday
        band = ''
    else:
        sql = sql_live
        band = ''
    con = sqlite3.connect('/var/log/datalog.db', detect_types=sqlite3.PARSE_DECLTYPES)
    with con:
        c = con.cursor()
        for val in ['temperature', 'humidity', 'pressure']:
            c.execute(sql.format(val))
            data[val] = c.fetchall()
            if band != '':
                c.execute(band.format(val))
                data[val + '_band'] = c.fetchall()
        return json.dumps(data)

def update_byhour():
    con = sqlite3.connect('/var/log/datalog.db', detect_types=sqlite3.PARSE_DECLTYPES)
    with con:
        c = con.cursor()
        # Get startDate for incremental update
        c.execute('SELECT MAX(logdate) FROM log_byhour;')
        startDate = c.fetchone()[0]
        if startDate == None:
            # Rascal24 arrival in UK
            startDate = datetime.datetime(2011, 12, 30)
        else:
            startDate = datetime.datetime.strptime(startDate, '%Y-%m-%d %H:%M:%S') + datetime.timedelta(hours = 1)
        # Get endDate
        c.execute("SELECT strftime('%Y-%m-%d %H:00:00','now');")
        endDate = c.fetchone()[0]
        # Update log_byhour
        for val in ['temperature', 'humidity', 'pressure']:
            c.execute(sql_update.format(val), (startDate, endDate))
            rows = c.rowcount
            if rows > 0:
                c.execute("DELETE FROM log WHERE logdate < datetime('now', '-36 hours');")
                # print '## update_byhour ## deleted ' + str(c.rowcount)
        return rows

def init(confirm):
    if confirm:
        logdate = datetime.datetime.utcnow()
        temperature = 21.2
        humidity = 56
        pressure = 29.375
        con = sqlite3.connect('/var/log/datalog.db')
        with con:
            cur = con.cursor()
            cur.execute('DROP TABLE IF EXISTS log;')
            cur.execute('CREATE TABLE log(logdate TIMESTAMP, temperature REAL, humidity REAL, pressure REAL);')
            cur.execute('INSERT INTO log (logdate, temperature, humidity, pressure) VALUES(?, ?, ?, ?)', (logdate, temperature, humidity, pressure))
        # Read back row to check, then delete
        con = sqlite3.connect('/var/log/datalog.db', detect_types=sqlite3.PARSE_DECLTYPES)
        con.row_factory = sqlite3.Row
        with con:
            c = con.cursor()
            c.execute('select * from log;')
            r = c.fetchone()
            print 'Logdate: ' + r['logdate'].strftime('%a, %d %b %Y %H:%M %Z')
            print 'Temperature: {0}'.format(r['temperature'])
            print 'Humidity: {0}'.format(r['humidity'])
            print 'Pressure: {0}'.format(r['pressure'])
            c.execute('delete from log;')
    else:
        print 'Set arg to True to initialise (deletes all data)'

def init_byhour(confirm):
    if confirm:
        logdate = datetime.datetime.utcnow()
        temperature = 21.2
        humidity = 56
        pressure = 29.375
        con = sqlite3.connect('/var/log/datalog.db')
        with con:
            cur = con.cursor()
            cur.execute('DROP TABLE IF EXISTS log_byhour;')
            cur.execute('CREATE TABLE log_byhour(logdate TIMESTAMP, temperature REAL, humidity REAL, pressure REAL);')
            cur.execute('INSERT INTO log_byhour (logdate, temperature, humidity, pressure) VALUES(?, ?, ?, ?)', (logdate, temperature, humidity, pressure))
        # Read back row to check, then delete
        con = sqlite3.connect('/var/log/datalog.db', detect_types=sqlite3.PARSE_DECLTYPES)
        con.row_factory = sqlite3.Row
        with con:
            c = con.cursor()
            c.execute('select * from log_byhour;')
            r = c.fetchone()
            print 'Logdate: ' + r['logdate'].strftime('%a, %d %b %Y %H:%M %Z')
            print 'Temperature: {0}'.format(r['temperature'])
            print 'Humidity: {0}'.format(r['humidity'])
            print 'Pressure: {0}'.format(r['pressure'])
            c.execute('delete from log_byhour;')
    else:
        print 'Set arg to True to initialise (deletes all data)'

part-of-server.py

# datalogger stuff
@rbtimer(30)
def log_value(num):
    import datalogger
#    artemp = pytronics.i2cRead(0x48, 0, 'I', 2)
#    ftemp = ((artemp[0] << 4) | (artemp[1] >> 4)) * 0.0625
    readings = pytronics.readWeatherBoard()
# print '## temp_log ## ' + str(ftemp)
    temperature = (float(readings['temperature']) - 32.0) * 0.5555
    humidity = readings['humidity']
    pressure = readings['pressure']
    datalogger.log(temperature, humidity, pressure)

@cron(-30, -1, -1, -1, -1)
def update_byhour(num):
    import datalogger
    rows = datalogger.update_byhour()
    if rows != 0:
        print '## updatelog ## added {0} row(s)'.format(rows)

@public.route('/datalogger.html')
def datalogger():
    return render_template('datalogger.html', title='Temperature Log', label0='Temp {0}C'.format(unichr(176)))

@public.route('/weather-station.html')
def weather_station():
    label0 = 'Temp {0}C'.format(unichr(176))
    label1 = 'Humidity [%]'
    label2 = 'Pressure [in Hg]'
    return render_template('weather-station.html', title='Weather Log', label0=label0, label1=label1, label2=label2)

@public.route('/getlog', methods=['POST'])
def getlog():
    import datalogger
    try:
        period = request.form['period']
    except KeyError:
        period = 'live'
    return datalogger.getlog(period)

weather-station.html

<!DOCTYPE html>
<html lang="en">
<head>
    <title>Weather station demo</title>
    {% include "include/rascal-head.html" %}
    <script type="text/javascript" src="/static/js/jqplot-plugins/jqplot.dateAxisRenderer.js"></script>
    <script type="text/javascript" src="/static/js/jqplot-plugins/jqplot.highlighter.js"></script>
    <style>
        #temperature-chart, #humidity-chart, #pressure-chart {
            margin-top: 20px;
            height: 400px;
            width: 800px;
        }
        .jqplot-title, .jqplot-axis, .status {
            color: #ddd;
        }
        .jqplot-table-legend-label {
            color: #111;
        }
        .btn-group {
            margin-top: 10px;
        }
        img.led {
            opacity: 0.4;
        }
        img.led.active {
            opacity: 1;
        }
        .close {
            opacity: 0.6;
        }
        .close:hover {
            opacity: 1;
        }
    </style>
</head>
<body>
    {% include "include/rascal-topbar.html" %}
    <div class="container">
        <div class="well rascal">
            <h1>{{ title }}</h1>
            <div id="temperature-chart"></div>
            <div id="humidity-chart"></div>
            <div id="pressure-chart"></div>
            <div class="row-fluid">
                <div class="span8">
                    <div class="btn-group" data-toggle="buttons-radio">
                        <button value="live" class="btn btn-default rascal active" style="width: 120px;">Live</button>
                        <button value="pastday" class="btn btn-default rascal" style="width: 120px;">Past Day</button>
                        <button value="pastweek" class="btn btn-default rascal" style="width: 120px;">Past Week</button>
                        <button value="pastyear" class="btn btn-default rascal" style="width: 120px;">Past Year</button>
                    </div>
                    <img id="LED" src="static/images/led.gif" width="10" class="led" />
                    <small id="status" class="status"></small>
                </div>
                <div class="span4">
                    <div class="btn-group">
                        <button id="capture" value="capture" class="btn btn-default rascal" style="float: right;">Capture Image</button>
                    </div>
                </div>
            </div> <!-- /row-fluid -->
        </div> <!-- /well -->

        <div id="captured-image" class="well rascal alert fade in" style="display:none;">
            <!-- <button type="button" class="close"><img src="/editor/static/images/file-icons/delete.png"></button> -->
            <img class="close" src="/editor/static/images/file-icons/delete.png">
            <p><small class="status">Right-click chart and choose Save Image As...</small></p>
            <div id="img-container"></div>
        </div> <!-- /well -->
    </div> <!-- /container -->
    <!-- {% include "include/doc-tab.html" %} -->
    <script type="text/javascript">

        var temperatureChartOptions = {
            legend: {
                show: true,
                location: "ne"
            },
            series: [
                { label: "{{ label0 }}", lineWidth: 3, showMarker: false, rendererOptions: { smooth: true } }
            ],
            axes: {
                xaxis: {
                    renderer: $.jqplot.DateAxisRenderer,
                    tickOptions: {formatString: '%a%n%H:%M'}
                },
                yaxis: {
                    min: 13.0,
                    max: 25.0
                    // tickOptions: {formatString: '%0.2f'}
                }
            },
            highlighter: {
                show: true,
                sizeAdjust: 7.5
            },
            seriesColors: [ "#cd2820" ]
        };

        var humidityChartOptions = {
            legend: {
                show: true,
                location: "ne"
            },
            series: [
                { label: "{{ label1 }}", lineWidth: 3, showMarker: false, rendererOptions: { smooth: true } }
            ],
            axes: {
                xaxis: {
                    renderer: $.jqplot.DateAxisRenderer,
                    tickOptions: {formatString: '%a%n%H:%M'}
                },
                yaxis: {
                    min: 0.0,
                    max: 100.0
                    // tickOptions: {formatString: '%0.2f'}
                }
            },
            highlighter: {
                show: true,
                sizeAdjust: 7.5
            },
            seriesColors: [ "#51a8cb" ]
        };

        var pressureChartOptions = {
            legend: {
                show: true,
                location: "ne"
            },
            series: [
                { label: "{{ label2 }}", lineWidth: 3, showMarker: false, rendererOptions: { smooth: true } }
            ],
            axes: {
                xaxis: {
                    renderer: $.jqplot.DateAxisRenderer,
                    tickOptions: {formatString: '%a%n%H:%M'}
                },
                yaxis: {
                    min: 25.0,
                    max: 32.0
                    // tickOptions: {formatString: '%0.2f'}
                }
            },
            highlighter: {
                show: true,
                sizeAdjust: 7.5
            },
            seriesColors: [ "#414243" ]
        };
        
        var
            period = 'live',
            interval = { live: 30*1000, pastday: 5*30*1000, pastweek: 30*60*1000, pastyear: 30*60*1000 },
            tickFormat = { live: '%a%n%H:%M', pastday: '%a%n%H:%M', pastweek: '%a%n%H:%M', pastyear: '%e %b%n%Y' },
            int_timer,
            capture_timeout,
            plot1,
            plot2,
            plot3;

        function updateGraph() {
            $('#LED').addClass('active');
            $.post("/getlog", { period: period }, function (response) {
                var data = $.parseJSON(response),
                    temperature = data.temperature,
                    humidity = data.humidity,
                    pressure = data.pressure,
                    temperature_band = data.temperature_band,
                    humidity_band = data.humidity_band,
                    pressure_band = data.pressure_band;
                console.log(response);
                console.log('updateGraph last data ' + temperature[temperature.length - 1][0]);
                if (temperature_band !== undefined) {
                    temperatureChartOptions.temperature[0].rendererOptions.bandData = temperature_band;
                }
                //} else {
                //    delete temperatureChartOptions.temperature[0].rendererOptions.bandData;
                //}
                $('#temperature-chart').empty();
                $('#humidity-chart').empty();
                $('#pressure-chart').empty();
                plot1 = $.jqplot('temperature-chart', [temperature], temperatureChartOptions);
                plot2 = $.jqplot('humidity-chart', [humidity], humidityChartOptions);
                plot3 = $.jqplot('pressure-chart', [pressure], pressureChartOptions);
                $('#status').text('Last update ' + new Date());
                setTimeout(function () {
                    $('#LED').removeClass('active');
                }, 500);
            }).error(function (jqXHR, textStatus, errorThrown) {
                $('#status').text('Update failed (' + errorThrown + ') ' + new Date());
                console.log('updateGraph: getlog: ' + textStatus + ': ' + errorThrown);
            });
        }

        function captureImage() {
            var options = {
                    x_offset: 0,
                    y_offset: 0,
                    backgroundColor: $('.well.rascal').css('background-color')
                },
                imgElem = $('#temperature-chart').jqplotToImageElem(options);
            $('#img-container')
                .empty()
                .append(imgElem);
            $("#captured-image").fadeTo(250, 1);
        }

        // If update in progress, wait until finished (max 10s)
        function captureIfYouCan() {
            var isBusy = $('#LED').hasClass('active');
            if (!isBusy) {
                captureImage();
            } else {
                if (capture_timeout < 20) {
                    capture_timeout += 1;
                    console.log('Capture Image: waiting for update ' + capture_timeout);
                    setTimeout(captureIfYouCan, 500);
                } else {
                    console.log('Capture Image: timed out waiting for update');
                }
            }
        }

        $('.btn').click(function () {
            var which = $(this).attr('value');
            if (which === 'capture') {
                capture_timeout = 0;
                captureIfYouCan();
            } else {
                int_timer = clearInterval(int_timer);
                period = which;
                console.log('Period set to ' + period + ' (refresh ' + (interval[period] / 1000).toString() + 's)');
                temperatureChartOptions.axes.xaxis.tickOptions.formatString = tickFormat[period];
                humidityChartOptions.axes.xaxis.tickOptions.formatString = tickFormat[period];
                pressureChartOptions.axes.xaxis.tickOptions.formatString = tickFormat[period];
                console.log(temperatureChartOptions.axes.xaxis.tickOptions.formatString);
                console.log(humidityChartOptions.axes.xaxis.tickOptions.formatString);
                console.log(pressureChartOptions.axes.xaxis.tickOptions.formatString);
                updateGraph();
                int_timer = setInterval(updateGraph, interval[period]);
            }
        });

        $(document).ready(function () {
            "use strict";
            period = 'live'
            updateGraph();
            int_timer = setInterval(updateGraph, interval[period]);
            $('.alert .close').live("click", function(e) {
                $(this).parent().fadeTo(350, 0, function () {
                    $(this).hide();
                });
            });
        });
    </script>
</body>
</html>