def number = /\W+(\d+)/
def eintraege = []
new File('weather.dat').text.eachMatch(/(?m)^${number * 3}.*/){ all, tag, max, min ->
        def spread = max.toInteger() - min.toInteger()
        eintraege << [tag, spread, min, max]
}
eintraege
        .sort{ it[1] }
        .each{ println String.format('Tag:%3s Spread:%3s Min:%3s Max:%3s', it*.toString().toArray()) }