The health care debate taught me something I didn’t know about Congress: lawmakers really don’t care about the weather. Or the day of the week.

In December, senators, aides and journalists slogged through Snowcalypse I on a Saturday for a major pre-dawn vote at the snow-entombed Capitol. They then reprised that bit of theatre on Christmas Eve morning, voting on health care reform before the sun came up.

Three blizzards paralyzed Washington in what became the snowiest winter in the city’s history. The nation’s capital recorded more snow than Arapahoe Basin in Colorado.

So everyone was looking forward to today, the first day of spring.

The forecast is for 74 degrees and sunny. The cherry blossoms along the Tidal Basin are on the verge of erupting into a sea of pink. It stays daylight past 7 pm now. Last weekend’s rain finally dissolved  the snowdrift isthmus that remained in the Pentagon parking lot. And the Washington Nationals are up to their old tricks, sporting a 3-12 record in Grapefruit League action.

Spring has sprung in Washington.

But guess who won’t be unpacking the golf clubs from the garage or going for a stroll along the Potomac this weekend?

Lawmakers, aides and journalists will embark on the Capitol for laborious Saturday and Sunday sessions in what could culminate in two, critical votes to advance the final health care bill to the Senate.

Talk of self-executing provisions, whip counts and the Byrd Rule will supplant trips to the garden store and street side brunches at Dupont Circle Cafés.

You’re worried about the field of 64 in March Madness? The only number that counts on Capitol Hill this weekend is 216.

With only 431 members in the House of Representatives right now, 216 is the new 218. That’s many votes House Speaker Nancy Pelosi (D-CA) needs to complete the health care bill and send it to the Senate.

But she’s not there yet.

On Friday, Pelosi scored the support of four Democrats who voted no on the initial health bill last November: Reps. Allen Boyd (D-FL), Suzanne Kosmas (D-FL), John Boccieri (D-OH) and Scott Murphy (D-NY). But dozens of lawmakers remain officially undecided. Or are believed to be in play as the vote creeps closer.

Rep. Bobby Rush (D-IL) voted yea last fall. Yet the Illinois Democrat spent 10 minutes on the phone Friday with President Obama. Rush’s support began to flag over a cut in assistance for the poor to purchase medications.

Rush remains the only person to ever defeat Mr. Obama in an election. He may have been able to stave off a primary challenge from the then-upstart state senator for his House seat a decade ago. But the question now is whether Rush can succumb to the power of the presidency.

“I moved from leaning no to very undecided,” Rush said after the presidential chat.

And as the hours tick toward Sunday’s vote, expect a lot of pressure from President Obama and other key Democrats as they try to lock down the votes.

When the bells sounded in the House late Friday afternoon, a swarm of reporters lined the hallway near the east door of the Capitol . The weather was nice Friday, so many lawmakers elected to walk to the votes outside from the House office buildings across the street. And reporters wanted to figure out where everyone stood.

“Are you getting any pressure?” I asked Rep. Michael McMahon (D-NY). McMahon’s a freshman from Staten Island who captured what had long been a Republican seat in 2008. He voted nay on the health bill last year.

“What town do you live in?” was McMahon’s retort.

“So you won’t confirm if they’ve called?” I asked, referring to the White House.

“No,” McMahon said with a smile, and walked back to the House chamber.

Then Rep. Glenn Nye (D-VA) materialized hiking up some marble stairs near a side entrance to the Speaker’s Lobby. Like McMahon, Nye’s another freshman Democrat who voted no last year and won what had been a Republican seat.

“Has the White House called you?” I queried.

“Actually, no,” Nye responded, never breaking stride and heading into the chamber to vote.

“Didn’t you ask him how he would vote?” probed the AP’s Erica Werner of me.

I told her that I didn’t. It was a conversation that lasted 3.8 seconds and covered all of 15 feet as Nye walked to the House chamber.

“I didn’t have him for the full hour,” I told Werner, a reference to Meet the Press when it promotes that it’s booked the vice president for an entire broadcast.

Rep. Steve Driehaus (D-OH), a freshman from a swing district, who voted yes last time, said he was still undecided for this round. Freshman Rep. Kathy Dahlkemper (D-PA) is in the same boat. Rep. Baron Hill (D-IN) is another lawmaker facing a tough race this fall. Yet he is undecided. And then came Rep. Rick Boucher (D-VA). Boucher voted no last November and could face his most-challenging election since the 1980s.

“I’m still reading the bill,” Boucher said as he breezed by.

A few minutes later, Rep. Earl Pomeroy (D-ND) arrived to vote.

“Still reading the bill,” answered Pomeroy.

Driehaus, Dahlkemper, Hill, Boucher and Pomeroy may truly be mulling their vote. But being undecided holds a special cachet. It’s an attention-getter. If you’re undecided this late in the game, the president and the speaker will focus on you. And perhaps that’s when you can cash in a favor. Even if it’s not on this bill.

Being undecided could signal something else. It may mean you’re a loyal Democrat. But this health care isn’t perfect for your district or it could harm your re-election prospects. But you don’t want to undermine the president. So you don’t publicly announce your stance one way or the other. You become a walking safety valve.

When the big vote starts, you don’t cast your vote early. You hide in the cloakroom. And if the leadership has the votes, you’re free to vote how you want. But if they’re coming up short, you can bet the leaders are going to come to you.

In case of emergency, break glass.

And the lobbying extends to the House floor.

On Friday, the House approved the Ocean, Coastal and Watershed Education Act and recognized the 50th anniversary of the first dive to the Challenger Deep in the Mariana Trench, the deepest point in the world’s oceans.

These stray bills are important to some lawmakers. But they were really a cover. They gave the House something to do while Team Pelosi and President Obama cajoled. And when the House called votes and all lawmakers reported to the floor, the Democratic leadership had even more time to twist arms.

During the final votes of the day, House Energy and Commerce Committee Chairman Henry Waxman (D-CA) was spied talking to Rep. Stephen Lynch (D-MA). Waxman is one of the chief sponsors of the bill. Lynch voted yes in the fall but now is a no. House Majority Leader Steny Hoyer (D-MD) conversed with Rep. Dennis Cardoza (D-CA). Cardoza voted for the bill but remains undecided.

I’m not privy to these conversations from my vantage point. But encounters like these can switch votes. Or at the very least, help the leadership team understand why a member is hedging and what can be done to placate them. Any good whip knows that brass-knuckle tactics usually fail. Leaders can achieve much more through cordial conversations like these.

Today the House debates the Public Lands Service Corps Act and recognizes the 65th anniversary of the Battle of Iwo Jima. But this just buys Pelosi more face time with undecided lawmakers.

This weekend is the Congressional version of the Stockholm Syndrome. In 1973, robbers held employees of a Stockholm bank hostage for days. Despite their ordeal, the hostages emerged embracing their captors’ motives.

Of course, House leaders couldn’t have forecast the nice weather this weekend. Things just turned out that way. But holding everyone inside over a beautiful, spring weekend on the heels of a harrowing winter will accomplish one of two things: it will either tick off the fence sitting lawmakers. Or it could convince undecided lawmakers to come around and help pass the bill once and for all.