President Trump said Monday that the large and boisterous crowds he's seeing as he holds rallies around the country is a good sign for Republicans as they head toward a midterm election that many think could give Democrats control of the House, and maybe even control of the Senate.

“The crowds at my Rallies are far bigger than they have ever been before, including the 2016 election. Never an empty seat in these large venues, many thousands of people watching screens outside,” Trump tweeted Monday morning. “Enthusiasm & Spirit is through the roof. SOMETHING BIG IS HAPPENING - WATCH!”

[Also read: Trump says US 'would end up' Venezuela if Democrats win midterms]

The midterm elections are less than a month away, and Trump has been holding several rallies each week in support of GOP candidates.

Rallies during the presidential election were notorious for being energetic and rowdy with thousands of attendees every time. Trump has admitted that midterm turnouts usually go against the incumbent in the White House, but has also said he's seen signs of a possible red wave this time around.

The GOP is working up its base to keep a majority in both chambers of Congress, while Democrats continue to claim a “blue wave” is coming in November that will give them the ability to block Trump's agenda.