The hot, muggy weather dampened daytime attendance at an eastern Iowa fair, and could provide clues to attendance at the Iowa State Fair, which opens Thursday.The 82nd annual Great Mississippi Valley Fair in Davenport ended its six-day run Sunday. Fair manager Bob Fox says daytime crowds were down Monday and Tuesday — the hottest days of the year, but people turned out when the sun went down. Despite the heat, the fair had the largest last-day attendance in its history.Phil Roberts, Davenport