Over half of Massachusetts is in the midst of an extreme drought, with the area in danger of major crop losses and water restrictions more than doubling since last week, the US Drought Monitor said Thursday.

Extreme drought, the second-most serious designation, now extends into most of Worcester County and into parts of Franklin and Hampton counties. Previously, the most extreme conditions were limited to Eastern Massachusetts, including all or parts of Bristol, Essex, Middlesex, Norfolk, Plymouth, and Suffolk counties, the monitor reported.

This year marks the first time Massachusetts has fallen into the “extreme’’ category since the government first collaborated with the University of Nebraska in 1999 to publish a weekly report of drought conditions nationally.

Less than 2 percent of the Bay State is free of drought conditions. The northwest corner of the state remains “abnormally dry.’’ About 38 percent of the state is in a severe drought and 8 percent in a moderate drought, the monitor reported.

The unusually dry conditions have prompted more communities to act to increase water supplies. On Wednesday, officials in Worcester activated an emergency connection to draw water from the Massachusetts Water Resources Authority at a monthly cost of $1.7 million.

Ashland also received approval Wednesday to tap into the supply, after previously instituting a water ban that barred residents from using automatic sprinklers, car washing, and filling ornamental pools, among other steps.

The widespread drought comes as Greater Boston experiences one of its driest periods in recent years. Rainfall is down 9.5 inches this year, and 18.5 inches since the start of 2015, according to the National Weather Service.

Meteorologist Lenore Correia said dry, high-pressure systems have been parked over the state for months. Occasionally, the conditions make way for storms, but none have brought enough rain to make a significant difference, he said.

Autumn could bring some relief, “but it’s hard to say at this point,’’ Correia said.

Showers and a threat of heavy rain are expected Sunday, as Tropical Storm Julia moves up the Eastern Seaboard, the weather service said Thursday.

Meanwhile, the lingering effect of a hot, dry summer has left Bay State farmers struggling with higher irrigation costs and hard decisions, as they strive to save crops.

“Some crops are not even worth harvesting,’’ said Fran Matheson, whose family owns Spring Brook Farm in Littleton. “You just have to till it and turn it under because they’re a disaster and a complete loss.’’

David Dumaresq, owner of Hill Orchard in Westford, had to let an entire crop of sweet corn die, to preserve enough water for other crops, he said.

“Where we are able to irrigate, harvests are great, but where we are running out of water, we have to decide what plants to water and what plants to let die,’’ he said.

Christian Smith, an owner of C.N. Smith Farm in East Bridgewater, said the drought forced the farm to irrigate all summer.

The lack of rainfall resulted in reductions in corn, pumpkins, and squash, and some crops were lost entirely, Smith said.

“Our winter squash didn’t produce anything,’’ he said.

Wilson Farms in Lexington is fully irrigated, but the drought has brought higher costs this summer, said owner Jim Wilson.

“It’s just very labor-intensive to keep the irrigation going the whole time,’’ Wilson said.

Some financial help is available for struggling farms. The state last week announced the Drought Emergency Loan Fund, which will make up to $1 million in loans ranging from $5,000 to $10,000 available to family farms and other small businesses affected by the prolonged drought.

The Massachusetts State Farm Service Agency, which provides federal financial assistance to the state’s farmers, has requested disaster assistance funds, said Jon Niedzielski, executive director.

“We think it will be signed next week,’’ he said.

Andy Rosen and Travis Andersen of the Globe staff contributed to this report. Dylan McGuinness can be reached at dylan.mcguinness @globe.com. Follow him on Twitter @dylmcguinness. Olivia Quintana can be reached at olivia.quintana@globe.com. Follow her on Twitter @oliviasquintana.