Forest fire experts usually base part of their annual fire outlook on whether the dominant weather pattern is the so-called El Niño or the opposite La Niña.
This year: "We're calling it 'La Nada,' " Spanish for "nothing," said Kristy Lund, interagency fire management officer for national forest lands and Saguaro National Park near Tucson.
Lund said that's because weather forecasters see no strong pattern of either El Niño or La Niña - terms that reflect whether sea-surface temperatures in the equatorial Pacific Ocean are warmer or cooler than normal.
"So we don't know what we're getting in terms of the monsoon this year - the timing or how strong it will be," Lund said Tuesday at a media briefing on the upcoming fire season.
Ken Drozd, warning coordination meteorologist with the National Weather Service, confirmed that "the precipitation outlook is inconclusive at this time."
"Officially, that is 'equal chances' or 33.3 percent chances of being either wet, dry or normal," Drozd said.
The uncertainty of the monsoon - along with other factors - results in an unpredictable fire outlook, Lund said.
"That means we try to prepare for anything," she said. "We will rely on situational awareness" - paying close attention to unfolding weather and other conditions.
Those other factors include an ongoing drought, winds, temperature fluctuations and the condition of "fine fuels" such as grasses.
"Invasive grasses such as buffelgrass are an increasing problem," Lund said. "The invasives have really changed the game for us in terms of fine fuels" - increasing the risk of fast-spreading fires.
Summer temperatures also play a role in fire predictions and management.
"The temperature outlook leans toward hotter-than-normal temperatures for the July, August and September period," Drozd said.
Last month was the second-warmest March on record for Tucson, the National Weather Service said. The month started off cool, but quickly warmed up, with three straight days of record highs by the middle of the month.
The average temperature in March was 65.7 degrees, about five degrees above normal. The average high was nearly 81 degrees; the average low was about 50 degrees. The warmest March on record was 66.7 degrees in 2004.
Contact reporter Doug Kreutz at email@example.com or at 573-4192. On Twitter: @DouglasKreutz