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Monday, September 22, 2025

September 22, 2025

BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA MONDAY, SEPTEMBER 22, 2025 ALL TIMES ARE…

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BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA MONDAY, SEPTEMBER 22, 2025 ALL TIMES ARE IN EASTERN STANDARD TIME (EST) SUNRISE: 0532E SUNSET:  1741E A MIX OF SUN AND CLOUDS WITH A BIT HIGHER HUMIDITY AND WARMER TEMPERATURES ON THIS FIRST DAY OF ASTRONOMICAL AUTUMN…. As we enter the Autumnal Equinox this afternoon, a bit more of a summery feel will greet us over the next couple of days. Today is featuring a mix of sun and clouds with temperatures warmer than they have been the past couple of days. Humidity levels are also a bit higher today, but all in all it’s still fairly pleasant for this time of year. Temperatures started the day in the low to mid 50s here on the summit, but did dip into the 40s in the lower surrounding areas. Readings have rebounded nicely into the low 70s by early this afternoon, which is a touch above normal for the date. Dew point values have been generally in the mid 50s, so while it’s a bit more humid than the past couple of days, it’s still at rather comfortable levels for the time being. Today is yet another day to feature a light wind. The average speed for the day so far is only around 6mph. The peak gust is 16mph so far, which occurred just after 11am this morning. Visibility has generally been between 30-50 miles for most of the day today. The maximum temperature so far today is 73F degrees, which is 3 degrees above the normal high of 70F. The minimum temperature since midnight is 53F degrees, which is equal to the normal low of 53F. ————————————————————– Today’s Observations: 7 A.M. Weather: Broken cirrus, few stratocumulus distant ENE-SE, few altocumulus/castellanus distant SW-NW-NNE Temperature: 58F; Dew Point: 55F; Relative Humidity: 89% Wind: ESE @ 3 kts, wind light Sea-level pressure: 1023.1 mb; 30.21 in. Hg: rising, then steady Visibility: 30 miles 6-hr Max temp: 58F 6-hr Min temp: 53F 24-hr Precip: 0.00 inches BHO SA 1155 E250 BKN 30 231/58/55/1103/021/ FEW SC DSNT ENE-SE FEW AC/ACC DSNT SW-NW-NNE PTCHY GF SE/ 8/581 51004 10058 20053 10 A.M. Weather: Broken cumulus, broken cirrus Temperature: 65F; Dew Point: 56F; Relative Humidity: 72% Wind: SW @ 5 kts, wind light Sea-level pressure: 1022.9 mb; 30.21 in. Hg: steady, then falling Visibility: 40 miles, hazy 3-hr Precip: 0.00 inches BHO SA 1455 E20 BKN 250 BKN 40 229/65/56/2205/021/ HAZY WND LGT/ 8/201 58002 1 P.M. Weather: Thin scattered cirrus, few cumulus all quadrants Temperature: 71F Dew Point: 53F; Relative Humidity: 54% Wind: SSW @ 7 kts Sea-level pressure: 1020.6 mb; 30.14 in. Hg: falling, then more slowly Visibility: 50 miles 6-hr Max temp: 73F 6-hr Min temp: 58F 6-hr Precip: 0.00 inches BHO SA 1755 250 -SCT 50 206/71/53/2107/014/ FEW CU ALQDS/ 8/201 56023 10073 20058 ————————————————————– SUMMARY FOR SUNDAY, SEPTEMBER 21, 2025 TEMPERATURE (DEGREES F) MAX…….68   NORMAL…..71 MIN…….52   NORMAL…..54 MEAN……60   NORMAL…..62 DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….-2 TOTAL DEPARTURE FOR THE MONTH………………………-17 [-1.0 DEGREES/DAY] HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026) TOTAL HEATING UNITS FOR YESTERDAY……………..5  DEPARTURE……..+1 TOTAL HEATING UNITS FOR THE MONTH…………….37  DEPARTURE…….-10 TOTAL HEATING UNITS FOR THE SEASON……………57  DEPARTURE……..-8 TOTAL HEATING UNITS LAST SEASON TO DATE……….33  DEPARTURE…….+24 COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025) TOTAL COOLING UNITS FOR YESTERDAY……………..0  DEPARTURE……..-2 TOTAL COOLING UNITS FOR THE MONTH…………….38  DEPARTURE…….-27 TOTAL COOLING UNITS FOR THE SEASON…………..710  DEPARTURE…….+49 TOTAL COOLING UNITS LAST SEASON TO DATE………753  DEPARTURE…….-43 PEAK WIND GUST (MPH): Note: Instruments designated #1 = Main Tower, #2 = South Tower, F420C, Contacting, Merlin, and Richards are all on Main Tower. E=Estimated F420C (Official)………..18 ESE  @   05:09 P.M. VECTOR #1 (1-Sec)……….19 SE   @   04:49 P.M. VECTOR #2 (1-Sec)……….17 ESE  @   05:10 P.M. DAVIS #1……………….17 ESE  @   05:09 P.M. DAVIS #2 ………………18 SE   @   05:10 P.M. RMY #1 (Instantaneous)…..19 ESE  @   05:09 P.M. RMY #2 (Instantaneous)…..18 ESE  @   05:10 P.M. MERLIN…………………16 SE RICHARDS (C5C) (Inst)……17 SSE  @   09:56 P.M. FASTEST MILE: CONTACTING ANEMOMETER/OFFICIAL………………13 SSE  @   10:23 P.M. MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..13 SSE  @   09:59 P.M. MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..13 ESE  @   05:10 P.M. MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………13 ESE  @   05:10 P.M. MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………14 SSE  @   05:11 P.M. MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..13 ESE  @   05:10 P.M. MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..13 ESE  @   05:10 P.M. MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………13 ESE  @   05:10 P.M. AVERAGE WIND SPEED AND DIRECTION: CONTACTING/OFFICIAL………5.8 SE [140 total miles] VECTOR #1……………….6.4 VECTOR #2……………….6.8 DAVIS #1………………..6.3 SE DAVIS #2………………..6.3 SE RMY #1………………….6.1 ESE RMY #2………………….6.8 ESE RICHARDS (C5C)…………..6.9 PRECIPITATION (INCHES) THROUGH THIS MORNING (EST): TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.15 TOTAL PRECIPITATION FOR THE MONTH…………..2.58 DEPARTURE…..-0.13 TOTAL PRECIPITATION FOR THE YEAR (2025)…….33.91 DEPARTURE…..-3.41 ————————————————————– PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER CALENDAR DAY DATA DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN)/SUN(%)/PEAK GUST/VEC1/RMY GUST PEAK GUST: F420C (Official) VEC1: Vector #1 1-second gust RMY:  R.M. Young #1 wind gust recording system (Instantaneous) TSTM: Thunderstorm day (thunder heard some time during day) ….: Data not yet available, records not finalized M:    Missing data 9/1   73/55/64/-5/0.00/221/28            23 NE  VEC1 23 ENE RMY 23 9/2   77/58/68/-1/0.00/714/91            18 ESE VEC1 19 ESE RMY 18 9/3   78/57/68/0/0.00/719/92             21 SSW VEC1 21 SSW RMY 21 9/4   81/56/69/+1/0.00/694/89            26 SSW VEC1 27 SSW RMY 28 9/5   82/63/73/+5/0.12/404/52            30 SSW VEC1 31 SSW RMY 33 9/6   84/64/74/+6/1.05/457/59            55 W   VEC1 55 W   RMY 57 TSTM 9/7   64/56/60/-7/0.97/000/00            16 WNW VEC1 16 NNE RMY 15 9/8   68/49/59/-8/0.00/508/66            21 NW  VEC1 21 NW  RMY 24 9/9   70/53/62/-5/0.00/697/91            22 ENE VEC1 23 E   RMY 23 9/10  65/54/60/-6/0.00/183/24            24 NE  VEC1 25 NE  RMY 25 9/11  77/51/64/-2/0.00/714/94            21 N   VEC1 17 N   RMY 18 9/12  71/56/64/-2/0.00/735/97            24 ENE VEC1 24 NNE RMY 23 9/13  76/55/66/+1/T/634/84               26 S   VEC1 26 S   RMY 25 9/14  79/57/68/+3/0.00/572/76            15 NE  VEC1 15 SW  RMY 15 9/15  72/57/65/0/0.00/689/92             20 N   VEC1 19 N   RMY 18 9/16  71/55/63/-1/0.00/403/54            20 E   VEC1 19 ESE RMY 19 9/17  71/55/63/-1/T/424/57               22 E   VEC1 22 E   RMY 21 9/18  75/61/68/+5/0.44/252/34            20 S   VEC1 20 S   RMY 20 TSTM 9/19  80/57/69/+6/0.00/715/97            24 N   VEC1 24 N   RMY 23 9/20  67/51/59/-4/0.00/…/..            20 SE  VEC1 19 SE  RMY 18 9/21  68/52/60/-2/0.00/…/..            18 ESE VEC1 19 SE  RMY 19 9/22 The low since midnight is 53F, the daily normal low is 53F. ————————————————————– SEPTEMBER DAILY RECORDS TO DATE NONE. ————————————————————– DAILY EXTREMES Temperature and precipitation records back to 1885, and wind records back to 1940 (e = estimated) RECORDS FOR SEPTEMBER 22 HIGH 90F IN 1895, 1914 LOW 30F IN 1904 (Earliest freeze) PRECIP 1.16 INCHES IN 2001 PEAK GUST 60 MPH SSW IN 1989 RECORDS FOR SEPTEMBER 23 HIGH 93F IN 1895,1914 LOW 33F IN 1904 PRECIP 2.67 INCHES IN 1994 PEAK GUST 62 MPH SSW IN 1989 TODAY’S REPORT PREPARED BY: Matt Douglas
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Blue Hill Observatory & Science Center · Legal

Data Use & Privacy Policy

Please read the full Policy before accessing Observatory data · Effective January 1, 2025

Notice: By accessing, downloading, or using any Blue Hill Observatory data or services, you unconditionally accept and agree to be bound by this Policy in its entirety. If you do not agree, you may not access or use Observatory data.
Effective January 1, 2025 · Milton, Massachusetts · bluehill.org
Part I — Data Use Policy
§ 01

Ownership and Proprietary Rights

All observational records, compiled datasets, metadata, database structures, and related materials provided by the Blue Hill Observatory & Science Center are the exclusive property of the Blue Hill Observatory & Science Center. The Observatory has maintained continuous weather observations at the summit of Great Blue Hill since 1885, and the entirety of that record — its compilation, structure, curation, and organization — constitutes a proprietary database protected under applicable United States law, including copyright law and common law database protections.

All rights not expressly granted in this Policy are reserved by the Observatory. No access to or use of Observatory data shall be construed as a waiver of any rights or as a license to use data beyond the scope expressly stated herein.

§ 02

Governing Law and Jurisdiction

This Policy shall be governed by and construed in accordance with the laws of the Commonwealth of Massachusetts, without regard to its conflict of law provisions. For interactions with international users, this Policy shall apply to the maximum extent permitted by applicable local law.

Any dispute arising from or related to this Policy shall be subject to the exclusive jurisdiction of the state and federal courts located in Norfolk County, Massachusetts. By accessing Observatory data, all users consent to personal jurisdiction in Massachusetts and waive any objection to the venue or inconvenience of such forum.

§ 03

Permitted Uses

Observatory data are made available for the following limited, non-commercial purposes only:

  • Personal study and analysis
  • Educational classroom use
  • Student projects
  • Non-commercial academic research
  • Publication of analyses, figures, models, or conclusions derived from the data, subject to the attribution requirements of Section 4

All other uses require prior written authorization from the Observatory.

§ 04

Attribution Requirement

Any use of Observatory data in any published, presented, or publicly distributed work must include the following verbatim acknowledgment:

“Data provided by the Blue Hill Observatory & Science Center, Milton, Massachusetts. Continuous weather observations since 1885.”

Failure to include proper attribution is a material violation of this Policy.

§ 05

Prohibited Uses

Unless explicitly authorized in writing, Users may not:

  • Resell, license, sublicense, or commercially exploit Observatory data in any form
  • Redistribute the dataset in whole or in part to any third party
  • Publish the dataset for download by third parties
  • Host, mirror, or archive the dataset on any external website, repository, or storage service
  • Upload the dataset to any public or institutional data repository
  • Provide the data through APIs, automated services, or subscription platforms
  • Incorporate the data into any commercial product, software, application, or service
  • Use the data for AI or machine learning systems intended for commercial use or external distribution
  • Use the data to create derivative datasets that enable reconstruction of the underlying observations
§ 06

Commercial Licensing

Organizations seeking to use Observatory data for commercial purposes must obtain a license prior to any such use. Licensing inquiries: data@bluehill.org.

§ 07

Automated Access

Automated scraping, bulk harvesting, or systematic downloading of Observatory data is strictly prohibited without prior written authorization.

§ 08

Enforcement and Remedies

Violation of this Policy may result in immediate revocation of data access, pursuit of legal remedies available under United States law, and referral to applicable authorities. The Observatory reserves all rights to seek injunctive relief, damages, and attorneys’ fees in connection with any unauthorized use of its data.

Part II — Privacy Policy
§ 09–10

Scope & Information Collected

This section governs the collection, use, storage, and disclosure of personal information from visitors to the Blue Hill Observatory website and users of its data services. The Observatory may collect contact information (name, email, organization) when voluntarily submitted, usage data including IP addresses and pages visited, and data download records.

§ 11–12

How We Use Information & Retention

Information is used solely for: responding to inquiries and licensing requests; monitoring and enforcing compliance with this Policy; improving website performance; and communicating Observatory news to opted-in users. The Observatory does not sell, rent, or share personal information with third parties for marketing purposes. Data access records may be retained indefinitely for compliance and enforcement purposes.

§ 13

International Users and Data Transfers

The Observatory is located in the United States. International users acknowledge their information will be processed in the United States under U.S. law. Users requiring specific data processing agreements under non-US law must contact data@bluehill.org before accessing data.

§ 14–16

Cookies, Security & Children’s Privacy

The Observatory website may use cookies for analytics and functionality. By continuing to use the site, users consent to cookie use. The Observatory implements reasonable measures to protect personal information but cannot guarantee absolute security. Observatory data services are not directed at children under 13.

Part III — General Provisions
§ 17–20

Modifications, Severability, Entire Agreement & Contact

The Observatory reserves the right to modify this Policy at any time. Updated versions will be posted at bluehill.org. Continued use of Observatory data following any modification constitutes acceptance of the revised Policy. This Policy constitutes the entire agreement between the User and the Observatory. Questions and licensing inquiries: Blue Hill Observatory & Science Center, Milton, Massachusetts — data@bluehill.org

By accessing, downloading, or using any Blue Hill Observatory data or services, you acknowledge that you have read, understood, and agree to be bound by this Policy.
Effective January 1, 2025 · Blue Hill Observatory & Science Center · Milton, Massachusetts
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