Here. Californ californians hardly ever think about insulating pipes to keep from bursting. Not really. Because it doesnt get cold enough. If this was alaska, everyone does it. But around here, it doesnt get below 32 often. Its not really thought about. But its a good idea. This is frost cloth. Reporter gardeners at summer winds nursery say consider covering your plants too, especially the newly planted ones. Damage from a freeze today could have lasting effects. A lot of times the cells in the plants might freeze. Youll see it in the form of leaf damage. Leaves the next day will probably be sunken, hanging. You might notice later on in the season that the plant doesnt grow very well in the beginning of the season just due to the stress and the cold. Reporter i saw a plant that i liked at that nursery for 300. Imagine losing that investment to the freeze. The pipe guys told me to replace a pipe could easily cost 150. So cover and protect and bring in your pets. That will save you money in the long run. Nannette miranda, nbc bay area news. We saw people covering their plants. Thats something many of us can do. What about people who have hundreds, thousands of acres of crops . Whats their protection . Reporter well, the farmers luckily are done with their harvests for the year. So a lot of crops have already been picked so will not be affected. But the citrus farmers in the sierra foothills, they still have crops and theyre keeping an eye. They wont get concerned until the temperatures drop to the 20s. Well find out when thats going to happen. Rob mayeda. Frost possible in parts of the day. 20s in the forecast right now . North bay, some spots may have a chance of dropping into the upper 20s. But the most part, the truly coldest hard freeze temperatures will be south of fresno and into the Central Valley. For the bay area weve dropped to the 40s around the north bay and east bay. Uppertries for now. And clear skies throughout the day. Ocean beach, gorgeous view. You didnt see fog or high clouds. Same view over to sonoma, sunny skies, a little bit of haze, breezy conditions in the hills. This is setting up cool, dry air in place for temperatures in the mid 20s. Again down towards the Central Valley off to the east around sacramento, 30 to 35 degree temperatures and close to that closer to San Francisco. It will be the winsheltered valleys of the north bay, trivalley, and south of san jose from 3 00 a. M. To 8 00 a. M. Tomorrow morning. Theyll have a chance of dropping close to freezing even for places like palo alto, maybe not quite 32. 34 overnight. Into downtown san jose, some of those buildings release a little bit of heat and write temperatures up a little bit. 35 degrees there. But other spots could be dropping down close to the upper 20s. A full look at that and how long the cold will stick around in our microclimate forecast. Right now, a look live at i80 in emeryville. Its going to take you to the sierra. And that is where the Christmas Eve storm covered the slopes with new snow and its attracting skiers from the bay area. That is stretch of freeway ever not crowded . This is donner ski ranch. Skiers say the snow you see now, it was dirt last year at this time. Coming up at 6 45, well take you to the sierra for a look at whats open for this weekend and the new year holiday seeing. How cold is it going to get where you live in track the weather with our nbc bay area app. You can get the very latest forecast. Youll also find temperatures for your neighborhood right there at your chilly fingertips. The app is free for iphones and android devices. Continuing coverage on the Police Shooting protests. Union square in San Francisco was packed today when a couple dozen protesters moved in for a black lives matter demonstration. The group says theyre doing it in solidarity with those in other cities across the country calling for an end to Police Brutality. Nbc bay areas Kimberly Terry live in berkeley where another event is going to get under way in just a few minutes now. Reporter thats right, terry. Tonights event will raise money for the family of Michael Brown, killed by a Police Officer in ferguson, missouri. Its happening at this hall in berkeley. A night of music with lyrics calls for social justice. Earlier a protest in the city focused on awareness of the issues between police and people of color. Black lives matter reporter a couple dozen demonstrators calling for an end to Police Brutality marched into a Bustling Union Square today. After holding a moment of silence, the names of more than 30 black People Killed by police were read. Alan bloomford. Black lives matter oscar grant. Black lives matter reporter to draw attention to their cause protesters are hoping tot their message out to as many people as they can, and they picked a good day to do it. The place was packed with shoppers and tourists. This is the time to celebrate and be with our families, also remember that our nation is at war right now. Theres a genocide being committed against black people every day, including the day after christmas, including christmas. Reporter the use of the word genocide sparked a debate among bystanders. Genocide is adolf hitler, rwanda. Reporter which ended in an argument over how to bring police and the community together. Youre putting it on an individual. Its policy that makes a difference. Reporter many of these passing by told us they think in some cases police are being unfairly targeted. The one thing everyone could agree on is that change is necessary. Its an important conversation thats way overdue. And black lives matter, latino lives matter, gay lives matter, cops lives matter. Reporter organizers of todays protest say this isnt something that will end any time soon. They say they will continue to protest until they see change. The market ended up slightly after a light day of trade iiniw closed at another record, staying above 18,000. Its almost as much a tradition as lastminute shopping postchristmas shopping. Consumers heading back to the mall for bargains. Business and tech reporter scott budman was there to meet them, scott, whatd you get me . Reporter its a surprise, terry, a postchristmas surprise, if you will. Tell you, the discounts are deep inside and so are the lines. People still streaming into bay area malls to take advantage of the day after christmas sales. Shoppers came from all over the bay area to find postholiday deals. Shopping for what . For her. I think we took advantage of the right day to come and shop. Reporter and not to drone on about this, but the day after christmas is big business here at the mall. Your phone . Yes, thanks to him. Day after christmas. Reporter big discounts and returns. Wrong sizes. Reporter brought thousands back for more. A little bit of both, yeah. We like going to the mall, hanging out. Me and the kids. Were struggling to see if we can find anything, any sales, Something Like that. I got the kindle on sale, 50 off. Very good. And also our abercrombie stuff for my daughter. Reporter its a tradition for shoppers of all ages. Brave the crowds one more time to save big money. Retailers tell us that this, the day after christmas, is the secondbusiest shopping day of the year. The busiest shopping day of the year, the saturday before Christmas Day. Scott, one of the problems, especially this time of year, is return fraud. What are some of the stores trying to do to cut back on that . Reporter it is a problem. Stores say it is an 11 billion a year problem. A lot of people buy things by ordering them online, then try to get money in the brick and mortar stores. They say what theyre trying to do is double and triplecheck the receipts to make sure youre not trying to scam them. Also hot at the malls today, gift cards. They were very hot items again this year. Today was the first chance to cash them in for actual merchandise. Oh, yeah, thats what i come here for. For what . Nordstroms, pandora, macys. You might as well cash them in. Ceb tower group which tracks Consumer Trends says were going to leave 1 billion in gift cards unused this year. 1 billion. Go look for them. 1 million and counting the haul for yesterdays opening day for the interview. The comedy about the assassination of north koreas dictator was released in only 320 theaters, made available to stream online. The movie was pulled after hackers, allegedly from north korea, targeted season though pictures and threatened attacks on theaters who showed the film. That didnt stop moviegoers who sold out screenings. Today, hackers are explaining why they played grinch on Christmas Day and kept gamers from going online. The group lizard squad shut down both xbox live and Playstation Networks by overwhelming the servers with fake user traffic. Website reports say the group hacked the systems, number one, for laughs. But also to get microsoft and sony to upgrade their security. The report says the group did it on Christmas Day to anger the largest amount of people and prompt angry calls to the companies. Gamers are still reporting Spotty Service today. The countdown to sunday begins as if the 49ers final game of the season, it could also be head coach Jim Harbaughs final game with the team. However harbaugh says he plans to enjoy his time on the sidelines. Im going to enjoy the players that i really enjoy being around. Enjoy the coaches. Going to have a lot of fun coaching this ball game. And there could be trouble brewing in niner nation. In sports well tell you about a new feud revealed on the team today. Neighbors across the street heard the screech, scream. A wakeup call from nature. These neighbors jolted out of bed because of a big cat. It is salmon spawning season. Im mark matthews. A report how the fish are faring coming up on this edition of nbc bay area news. 40s and 50s right now. But by tomorrow morning, on our way down to the low 30s. Patchy frost part of the forecast as we start the weekend and throughout your sevenday forecast. Well have a look at that when we come back. South bay officers are searching for whoever may be responsible for three car fires set in a couple of hours. Firefighters found this suv in san joses evergreen neighborhood earlied y ed ttues morning. A couple of hours later two more car fireser in delmar high school. According to arson investigators theres evidence the fires are not related. Police say arson is suspected in each of those fires. A peninsula lawmaker is calling for a new measure to curb repeat drunk drivers introducing legislation that would require all californians convicted of a dui offense to install vehicle ignition locks that detect blood alcohol levels saying repeat offenders make up onethird of dui convictions that according to a 2011 study, ignition locks cut down on repeat offenses by 67 . The peninsula lawmaker will unveil the measure monday in redwood city. Uber is facing a new Class Action Lawsuit alleging the San Franciscobased company misrepresents a 1 safe ride fee to its customers. This comes on the heels of both the San Francisco and l. A. District attorneys suing that company over the same thing. This lawsuit claims the background checks for drivers falls well short of industry standards. Uber has not commented on this latest lawsuit. Its now or never. Those hit hard by the napa quake back in august have until monday to apply for government aid. Fema still offering help in person, online, over the phone for people in napa and solano counties whose homes and businesses were affected by the magnitude 6. 0 quake. Disaster assistance includes grants for homeowners and representers to pay for rent, essential home repairs, other disasterrelated needs not covered by insurance. So far fema has helped 2,500 people. Go to nbcbayarea. Com and search napa quake to learn how did apply for assistance. Hills borrow residents on edge after a Mountain Lion was spotted. Police warning people to be extra vigilant. The sighting happened on el cerrito avenue near brentwood road in a residential area. A homeowner says he first heard rustling in a tree over his house. Awakened us. Then seconds later our window was open, and there was a high screech, scream, like a Mountain Lion scream, and i screamed right back at it to scare it away. Then i heard a lighter scream just a few seconds later. He called police. When officers got there, they found a dead deer in the yard. That might have been that weaker scream that he was talking about. They believe the deer was mauled by that Mountain Lion. Now theyre telling neighbors and passersby to keep a lookout for that Mountain Lion since that spot is not far from two schools. New at 6 00, heavy rains and swollen creeks. Biologists are not seeing a rise in the number of salmon spawning in marin county creeks. Mark matthews went looking today with a wildlife biologist from the marin municipal Water District. Reporter we are seeing three times more water this year than last year. We are not seeing three times the number of fish. We do surveys where we walk through the creek. Reporter Fishery Program manager Gregory Andrew is counting the number of salmon nesting sites or reds. Were up to about 70 reds total. Reporter he says average would be 250. The numbers right now are on track for a little more than half that. There is a salmon down there. Reporter he points out a male and female coho getting ready to spawn. The marin municipal Water District has been tracking the population of these fish for decades and they have seen wild swings, from 1,300 fish to 50 six years ago. Andrew ice used to say the population was stable but tenuous. To say theyre stable now is sort of a stretch. Reporter people come to see them late november to midjanuary. Its quite something to experience. Yeah. Reporter and regulars did notice a dropoff during the drought. The last few years have been theyve been pretty thin. Reporter the salmon are a keystone species in this ecosystem. Wildlife and insects feed on salmon carcasses after the fish spawn. Even trees take up the nutrients. The hope was that with more water, we would see more fish. It has not happened. Nevertheless, andrew says coming out here and just looking actually helps. And bring your children out with you so that they have a sense of importance of salmon populations being good for them and their lives in california. I think what you want to try to get people to do. Reporter mark matthews, nbc bay area news. Lets get the latest on our microclimate forecast. We know this much. Its going to be cold. How cold . Were watching temperatures closely. Our rainfall percentages have averaged so far through the wet month of december, over 100 to 200 of average. There will be one more opportunity maybe to get a little more coming in around the 30th. More on that coming up in a moment. Right now in San Francisco, clear skies. 56 degrees. Still breezy out there. Around San Francisco, one of the few spots that should stay closer to the mid 40s for overnight temperatures. Its the north bay and out toward the inland east bay around the trivalley and areas south of san jose that have a chance for 30s. Canadian air conditioning continues down the west coast. Dry air settling into the bay area with clear skies. So without the low clouds acting like a blanket and the dry air in place, well see lows dipping into the 30s. We have an impressive system to the west. But High Pressure just off to the east acting like a wall thats not going to allow that system to get through. Instead for the next couple of nights and especially i think more for saturday morning as opposed to sunday morning, were going to have those temperatures dropping into the 30s and windsheltered valleys. Another chance of colder temperatures toward next week. Tonight, coldest spots likely around santa rosa and napa, should drop below 32 degrees briefly overnight around sunrise. You could see san jose closer to 35. 31 degrees in livermore. More 30s as we go through the weekend. Once we lose morning temperatures, which will be cold, like today, afternoon temperatures nice. As we see numbers starting to climb into the upper 50s around san jose, mid to upper 50s near San Francisco, and the north bay too. Despite the fact youre starting at 30, we should see almost a 30degree swing in temperatures for the afternoon with that sunshine and the trivalleys seeing highs in the upper 50s. Frost one part of the story. As we head toward the beginning of next week there is potential for an even colder system to drop down from the north. That could place our highs in the 40s and 50s. With that cold air in place, fit comes over the bay area overnight, there is that opportunity for some low snow levels as well. Especially out toward the sierra. Maybe 2,000 to 3,000 feet. Well see how much moisture this system is bringing and the impact over the next seven days in your full forecast in our next half hour. Still ahead, your money falling through the cracks. Were adding up the tab for state money mismanagement. As if having a tesla wasnt enough, the new perk for drivers. Above and beyond. Two officers turn into doctors when a woman goes into labor on the subway. A followup on the fire that burned down two homes in San Franciscos potrero hill neighborhood on Christmas Day. Authorities say that fire caused more than 1. 3 million in damages and it killed two cats. The fire was reported about 6 30 a. M. On the 200 block of mississippi street. The fire went to three alarms before it was put out about four hours later. The cause of the fire still under investigation. A state agency is following the money and adding up the cost of bad behavior. A new report