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Wednesday, September 17, 2025

September 17, 2025

BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA WEDNESDAY, SEPTEMBER 17, 2025 ALL TIMES ARE…

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BLUE HILL METEOROLOGICAL OBSERVATORY MILTON, MASSACHUSETTS ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA WEDNESDAY, SEPTEMBER 17, 2025 ALL TIMES ARE IN EASTERN STANDARD TIME (EST) SUNRISE: 0527E SUNSET:  1750E MORE CLOUDS THAN SUN TODAY AS A SYSTEM SPINS TO OUR SOUTH…. We had some fog early this morning, but otherwise the sky has featured a lot of clouds throughout the day with breaks of sunshine. All in all it’s been a pretty nice day however. Temperatures are a bit on the cool side again today thanks to the wind off the ocean. Readings did reach the low 70s for a time, but has dipped back into the upper 60s early this afternoon. Dew point values have been generally hanging out in the mid to upper 50s most of the day. Winds have been fairly steady out of an easterly direction. The speed has been averaging at around 9mph for the day so far. The peak gust so far for the day is 22mph, which occurred just before 9am this morning. Visibility was as high as 70 miles for a time early this morning, but decreased to around 50 miles by mid morning and remained there through early this afternoon. The maximum temperature so far today is 71F degrees, which is 1 degree below the normal high of 72F. The minimum temperature since midnight is 55F degrees, which is equal to the normal low of 55F. ————————————————————– Today’s Observations: 7 A.M. Weather: Scattred altostratus, broken altocumulus, broken cirrostratus few stratus fractus all quadrants, virga all quadrants Temperature: 58F; Dew Point: 57F; Relative Humidity: 97% Wind: ENE @ 10G17 kts Sea-level pressure: 1022.6 mb; 30.20 in. Hg: falling, then more rapidly Visibility: 70 miles, 10 miles ESE-SSW 6-hr Max temp: 58F 6-hr Min temp: 55F 24-hr Precip: 0.00 inches BHO SA 1155 100 SCT E150 BKN 220 BKN 70 226/58/57/0610G17/020/ FEW STFRA ALQDS VIRGA ALQDS VSBY 10 ESE-SSW/ 8/776 58013 10058 20055 10 A.M. Weather: Scattered stratocumulus, scattered altostratus, broken altocumulus/castellanus broken cirrostratus, broken cirrus Temperature: 70F; Dew Point: 57F; Relative Humidity: 63% Wind: E @ 7 kts Sea-level pressure: 1023.0 mb; 30.21 in. Hg: rising, then falling Visibility: 50 miles 3-hr Precip: 0.00 inches BHO SA 1455 20 SCT 90 SCT E120 BKN 220 BKN 250 BKN 50 230/70/57/0907/021/ 8/576 50004 1 P.M. Weather: Broken altocumulus/castellanus, broken cirrostratus, broken cirrus, few stratocumulus distant all quadrants, virga distant SE-SW Temperature: 69F Dew Point: 59F; Relative Humidity: 70% Wind: NE @ 9 kts Sea-level pressure: 1021.8 mb; 30.17 in. Hg: rising, then falling Visibility: 50 miles 6-hr Max temp: 71F 6-hr Min temp: 58F 6-hr Precip: 0.00 inches BHO SA 1755 E120 BKN 180 BKN 250 BKN 50 218/69/59/0409/017/ FEW SC DSNT ALQDS VIRGA DSNT SE-SW/ 8/586 58012 10071 20058 ————————————————————– SUMMARY FOR TUESDAY, SEPTEMBER 16, 2025 TEMPERATURE (DEGREES F) MAX…….71   NORMAL…..73 MIN…….55   NORMAL…..56 MEAN……63   NORMAL…..64 DEPARTURE FROM 30-YEAR (1991-2020) NORMAL…………….-1 TOTAL DEPARTURE FOR THE MONTH………………………-21 [-1.5 DEGREES/DAY] HEATING DEGREE DAYS (SEASON: JUL 2025 THRU JUN 2026) TOTAL HEATING UNITS FOR YESTERDAY……………..2  DEPARTURE……..-1 TOTAL HEATING UNITS FOR THE MONTH…………….24  DEPARTURE……..-4 TOTAL HEATING UNITS FOR THE SEASON……………44  DEPARTURE……..-2 TOTAL HEATING UNITS LAST SEASON TO DATE……….21  DEPARTURE…….+23 COOLING DEGREE DAYS (SEASON JAN 2025 THRU DEC 2025) TOTAL COOLING UNITS FOR YESTERDAY……………..0  DEPARTURE……..-2 TOTAL COOLING UNITS FOR THE MONTH…………….31  DEPARTURE…….-22 TOTAL COOLING UNITS FOR THE SEASON…………..703  DEPARTURE…….+54 TOTAL COOLING UNITS LAST SEASON TO DATE………741  DEPARTURE…….-38 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)………..20 E    @   12:13 A.M. VECTOR #1 (1-Sec)……….19 ESE  @   12:23 A.M. VECTOR #2 (1-Sec)……….19 ENE  @   12:13 A.M. DAVIS #1……………….19 E    @   12:13 A.M. DAVIS #2 ………………19 E    @   12:13 A.M. RMY #1 (Instantaneous)…..19 E    @   12:13 A.M. RMY #2 (Instantaneous)…..20 ENE  @   12:13 A.M. MERLIN…………………19 NE RICHARDS (C5C) (Inst)……18 E    @   12:13 A.M. FASTEST MILE: CONTACTING ANEMOMETER/OFFICIAL………………13 E    @   12:18 A.M. MAXIMUM 2-MINUTE VECTOR #1 AVERAGE…………..14 E    @   12:24 A.M. MAXIMUM 2-MINUTE VECTOR #2 AVERAGE…………..15 ENE  @   12:14 A.M. MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………16 E    @   12:15 A.M. MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………16 E    @   12:15 A.M. MAXIMUM 2-MINUTE RMY #1 AVERAGE……………..15 ENE  @   12:15 A.M. MAXIMUM 2-MINUTE RMY #2 AVERAGE……………..15 ENE  @   12:14 A.M. MAXIMUM 2-MINUTE RICHARDS (C5C) AVERAGE………15 ENE  @   12:15 A.M. AVERAGE WIND SPEED AND DIRECTION: CONTACTING/OFFICIAL………6.5 ENE [156 total miles] VECTOR #1……………….6.5 VECTOR #2……………….7.3 DAVIS #1………………..7.0 ENE DAVIS #2………………..6.9 ENE RMY #1………………….6.8 ENE RMY #2………………….7.2 NE RICHARDS (C5C)…………..7.3 PRECIPITATION (INCHES) THROUGH THIS MORNING (EST): TOTAL PRECIPITATION 24 HRS ENDING 7 A.M……..0.00 DEPARTURE…..-0.14 TOTAL PRECIPITATION FOR THE MONTH…………..2.14 DEPARTURE…..+0.17 TOTAL PRECIPITATION FOR THE YEAR (2025)…….33.47 DEPARTURE…..-3.11 ————————————————————– 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/…/..            15 NE  VEC1 15 SW  RMY 15 9/15  72/57/65/0/0.00/…/..             20 N   VEC1 19 N   RMY 18 9/16  71/55/63/-1/0.00/…/..            20 E   VEC1 19 ESE RMY 19 9/17 The low since midnight is 55F, the daily normal low is 55F. ————————————————————– 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 17 HIGH 87F IN 2015 LOW 38F IN 1959 PRECIP 2.73 INCHES IN 1933 PEAK GUST 60 MPH WNW IN 1999 RECORDS FOR SEPTEMBER 18 HIGH 88F IN 1906 LOW 36F IN 1919 PRECIP 4.25 INCHES IN 1996 PEAK GUST 77e MPH WNW IN 1948 TODAY’S REPORT PREPARED BY: Amanda Joly/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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