This April was the coolest one in Tucson since 1999, the National Weather Service reported Monday.

The average temperature for April 2010 was 65.4 degrees, slightly cooler than the normal average April temperature, 66 degrees, the weather service reported. The official recording for rainfall also was slightly below normal. The station at Tucson International Airport received 0.23 inches of rain in April, compared to a normal of 0.28.

The temperature still hasn’t officially hit 90 degrees in Tucson, which is very late compared to recent years. Since 2000, the average first 90 degree temperature has been on March 26th.

The high temperature could hit 90 on Tuesday or Wednesday, the service forecasts. Either day would be among the dozen latest dates for a year’s first 90-degree temperature in recorded Tucson history.

The latest 90-degree temperature ever recorded in Tucson was on May 16 in both 1933 and 1905.