Supplemental Prospectus (Form 424B3)

Filed Pursuant to Rule 424(b)(3)

Registration No. 333-284614

PROSPECTUS SUPPLEMENT No. 7

(to the prospectus dated April 25, 2025)

Rain Enhancement Technologies Holdco, Inc.

5,000,000 Shares of Class A Common Stock Underlying Warrants (For Issuance)

5,914,057 Shares of Class A Common Stock (For Resale)

This prospectus supplement No. 7 (this "Supplement") supplements, updates and amends the information contained in the prospectus dated April 25, 2025 (the "Prospectus") relating to the issuance of shares of Class A common stock, par value $0.0001 per share (the "Class A Common Stock"), of Rain Enhancement Technologies Holdco, Inc. (the "Company") upon the exercise of warrants of the Company ("Warrants") and the resale from time to time of shares of Class A Common Stock by the selling shareholders (including their transferees, donees, pledgees and other successors-in-interest) named in the Prospectus. This Supplement updates and supplements the Prospectus.

This Supplement is being filed to update and supplement the information previously included in the Prospectus with the information contained in the Company's Current Report on Form 8-K filed with the SEC on December 29, 2025 (the "Form 8-K"). Accordingly, we have attached the Form 8-K to this Supplement. You should read this Supplement in conjunction with the Prospectus. This Supplement is not complete without, and may not be delivered or used except in conjunction with, the Prospectus, including any amendments or supplements thereto. This Supplement is qualified by reference to the Prospectus, except to the extent that the information provided by this Supplement supersedes information contained in the Prospectus. Capitalized terms used in this Supplement have the meanings given to them in the Prospectus.

Our shares of Class A Common Stock and Warrants are listed on the Nasdaq Stock Market LLC ("Nasdaq") under the symbols "RAIN" and "RAINW," respectively. On December 29, 2025, the closing price of our Class A Common Stock was $7.94 per share and the closing price for our Warrants was $0.39 per Warrant.

We are an "emerging growth company" as defined under the federal securities laws, and, as such, may elect to comply with certain reduced public company reporting requirements for this and future filings.

INVESTING IN OUR SECURITIES INVOLVES RISKS. YOU SHOULD CAREFULLY CONSIDER THE RISK FACTORS SET FORTH UNDER THE SECTION ENTITLED "RISK FACTORS" ON PAGE 12 OF THE PROSPECTUS, BEFORE MAKING ANY DECISION WHETHER TO INVEST IN OUR SECURITIES.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this Supplement or the accompanying Prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is December 29, 2025.

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): December 22, 2025

RAIN ENHANCEMENT TECHNOLOGIES HOLDCO, INC.

(Exact name of registrant as specified in its charter)

Massachusetts		001-42460		99-3527155
(State or other jurisdiction of incorporation)		(Commission File Number)		(IRS Employer Identification No.)

4851 Tamiami Trail N, Suite 200

Naples, FL 34103

(Address of principal executive offices, including zip code)

Registrant's telephone number, including area code: 339-222-6714

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐

Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐

Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐

Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Class A common stock, par value $0.0001 per share		RAIN		The Nasdaq Stock Market LLC
Redeemable warrants, each whole warrant exercisable for one share of Class A common stock at an exercise price of $11.50		RAINW		The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On December 22, 2025, the board of directors ("Board") of Rain Enhancement Technologies Holdco, Inc. (the "Company") increased the size of the Board from seven to eight directors. Also on December 22, 2025, pursuant to the terms of the Company's Amended and Restated Articles of Organization and the Company's Bylaws, the holders of the Company's Class B common stock, par value $0.0001 per share (the "Class B Common Stock"), unanimously approved by written consent the appointment of Mr. David C. Sylvester to fill the resulting vacancy.

Mr. Sylvester was appointed to serve as a Class II director with a term expiring at the Company's 2027 annual meeting of stockholders. Mr. Sylvester will serve on the Audit Committee of the Board. The Board has determined that Mr. Sylvester is an independent director and meets the applicable standards for Audit Committee service under both the Nasdaq Stock Market Rules and Rule 10A-3 under the Securities Exchange Act of 1934.

In connection with his appointment to the Board, Mr. Sylvester entered into a Director Agreement consistent with the Company's form of Director Agreement that is filed as Exhibit 10.1 to the Company's Current Report on Form 8-K, filed with the Securities and Exchange Commission on April 7, 2025. The grant of restricted stock to Mr. Sylvester pursuant to the Director Agreement was deferred by the Board. Additionally, in connection with his appointment to the Board, Mr. Sylvester entered into an Indemnity Agreement consistent with the Company's form of Indemnity Agreement that is filed as Exhibit 10.1 to the Company's Current Report on Form 8-K, filed with the Securities and Exchange Commission on January 7, 2025.

There are no arrangements or understandings between Mr. Sylvester and any other persons pursuant to which Mr. Sylvester was selected as a director of the Company. There are no family relationships between Mr. Sylvester and any of the Company's other directors or executive officers and Mr. Sylvester does not have any direct or indirect material interest in any transaction required to be disclosed pursuant to Item 404(a) of Regulation S-K.

Item 5.07 Submission of Matters to a Vote of Security Holders.

The information set forth in Item 5.02 of this Current Report on Form 8-K is incorporated by reference into this Item 5.07 to the extent required. Pursuant to the Company's Amended and Restated Articles of Organization and the Company's Bylaws, until the Voting Threshold Date (as defined in the Company's Amended and Restated Articles of Organization) only the holders of Class B Common Stock are entitled to fill vacancies occurring in the Board as a result of an increase in the authorized number of directors. As the appointment of Mr. Sylvester was approved by unanimous written consent, there are no votes against, withholding or abstaining, and no broker non-votes in relation to this matter.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: December 29, 2025	RAIN ENHANCEMENT TECHNOLOGIES HOLDCO, INC.
	By:	/s/ Oanh Truong
	Name:	Oanh Truong
	Title:	Interim Chief Financial Officer