The Casco Bay Report
Wind, water and sky between Portland Head Light and Bailey Island — read off the instruments each hour and set down in plain language.
Sunday, September 20·Today’s reckoningCompiled 1:28 AM EDT
The State of the Bay
Taken at the hour from the harbour sensors, the offshore buoy and the forecast grid.
53°F
clear sky
feels 49°
The air
Dew point47°
Humidity80%
Cloud cover1%
Visibility37.1 mi
Barometer1022.4 mb
steady
Sun strength0.0
low
Fog0 of 100
unlikely
The wind
out of the west-southwest
Force 3 · Gentle breeze
WSW · 248°
sheltered. Mostly blocked by the mainland. Chop stays short and steep rather than swelly.
60°F
water — brisk
The sea
Significant height1.3 ft
smooth
Dominant period3 s
Ground swell0.7 ft
at 12 seconds
Current at the entrance0.2 kt
ebbing, setting SE
Fine for a swim, but expect a gasp on entry. Exhaustion sets in after 2–7 hours.
The Tide at Portland
NEAP TIDESPredicted from NOAA station 8418150 and checked against the measured water level. Heights are feet above mean lower low water.
2.1ft
and making
+0.59 ft/hr
| Tide | Time | Height |
|---|---|---|
| Low | 12:39 AM | 1.6 |
| High | 6:56 AM | 7.5 |
| Low | 12:44 PM | 2.3 |
| High | 7:06 PM | 8.5 |
| LowMon | 1:40 AM | 1.6 |
| HighMon | 7:55 AM | 7.6 |
Next high6:56 AM
5h 28m from now
Range today6.9 ft
76% of the 9.1 ft mean
Against prediction+0.24 ft
Close to book value
The Sun and the Moon
12h 16m of daylight, losing 3 min a dayComputed for 43°42′ N, 70°09′ W — the middle of the bay, between Long Island and Chebeague.
The sun
First light civil dawn | 5:56 AM |
Sunrise golden until 7:03 AM | 6:25 AM |
Highest 47.2° above the horizon | 12:33 PM |
Golden hour the good light | 6:03 PM |
Sunset | 6:41 PM |
Last light full dark at 8:18 PM | 7:10 PM |
The moon
Waxing Gibbous
66.9% lit · 9 days old
Rises3:56 PM
Sets12:41 AM
Next fullSep 26
Next newOct 10
Feeding periods24
The old solunar reckoning: fish move hardest when the moon is on the meridian — overhead or underfoot — and again at its rising and setting. Lay a major period over a running tide and that is your hour.
| Period | From | To |
|---|---|---|
| Moon underfootmajor | 6:50 AM | 8:50 AM |
| Moonriseminor | 3:26 PM | 4:26 PM |
| Moon overheadmajor | 7:20 PM | 9:20 PM |
| Moonsetminor | 12:11 AM | 1:11 AM |
Notices to Mariners
What would catch you out today, and what is worth going out for.
Wind against tide
Around 9:00 AM the breeze opposes the current. Seas will stand up short and steep — worse than the 1.1 ft height suggests, especially at the harbor entrance.
Wind peaks
SSE 13 kt, gusts 16 around 9:00 AM.
Neap tides — 6.9 ft range
A gentle swing today. Weaker currents through the gut and less flat exposed at low water.
Evening golden hour
Starts 6:03 PM, sunset 6:41 PM, civil dusk 7:10 PM. Day length is shrinking by 3 min a day right now.
Best window 8:00 AM
SSE 9 kt, 1.1 ft seas, ebb tide. Best combination of breeze and sea state in the next 24 hours.
Hour by Hour
The next day and night, read off the forecast grid and joined to the tide and the current at the harbour entrance.
| Hour | Weather | Air | Wind | Gust | Sea | Per. | Tide | Set | Curr. | Rain | Vis. | Fog |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| now | Clear sky | 53° | WSW 7 | 9 | 1.0 | 8s | 1.7 | low | 0.3 | 0% | 37 | 0 |
| 2 AM | Clear sky | 53° | WSW 9 | 11 | 1.0 | 8s | 2.3 | flood | 0.0 | 0% | 40 | 0 |
| 3 AM | Clear sky | 53° | WSW 7 | 9 | 1.0 | 8s | 3.5 | flood | 0.3 | 0% | 36 | 0 |
| 4 AM | Clear sky | 52° | WSW 6 | 7 | 1.0 | 8s | 5.0 | flood | 0.4 | 0% | 35 | 0 |
| 5 AM | Clear sky | 53° | SW 3 | 5 | 1.0 | 8s | 6.3 | flood | 0.3 | 0% | 38 | 0 |
| 6 AM | Clear sky | 54° | S 3 | 5 | 1.0 | 8s | 7.2 | flood | 0.1 | 0% | 39 | 0 |
| 7 AM | Clear sky | 55° | SSE 4 | 10 | 1.1 | 8s | 7.5 | high | 0.0 | 0% | 38 | 9 |
| 8 AM | Partly cloudy | 58° | SSE 9 | 12 | 1.1 | 7s | 7.1 | ebb | 0.2 | 0% | 41 | 9 |
| 9 AM | Mainly clear | 58° | SSE 13 | 16 | 1.1 | 7s | 6.1 | ebb | 0.5 | 1% | 49 | 0 |
| 10 AM | Overcast | 58° | SSE 13 | 16 | 1.2 | 6s | 4.7 | ebb | 0.7 | 1% | 46 | 0 |
| 11 AM | Overcast | 59° | SSE 12 | 15 | 1.3 | 5s | 3.4 | ebb | 0.6 | 3% | 47 | 9 |
| 12 PM | Overcast | 59° | SSE 12 | 13 | 1.3 | 5s | 2.5 | ebb | 0.4 | 8% | 49 | 9 |
| 1 PM | Overcast | 59° | SSE 11 | 13 | 1.3 | 5s | 2.4 | low | 0.2 | 17% | 47 | 9 |
| 2 PM | Light drizzle | 59° | SSE 9 | 10 | 1.3 | 5s | 2.9 | flood | 0.1 | 26% | 38 | 9 |
| 3 PM | Drizzle | 59° | SSE 9 | 11 | 1.3 | 5s | 4.0 | flood | 0.3 | 41% | 20 | 9 |
| 4 PM | Drizzle | 59° | SSE 11 | 12 | 1.4 | 5s | 5.6 | flood | 0.5 | 48% | 21 | 9 |
| 5 PM | Heavy drizzle | 57° | ESE 7 | 12 | 1.4 | 5s | 7.1 | flood | 0.3 | 47% | 18 | 9 |
| 6 PM | Overcast | 58° | E 11 | 12 | 1.4 | 5s | 8.1 | flood | 0.2 | 45% | 36 | 9 |
| 7 PM | Drizzle | 58° | E 12 | 13 | 1.4 | 5s | 8.5 | high | 0.0 | 44% | 19 | 0 |
| 8 PM | Light drizzle | 57° | ENE 13 | 14 | 1.4 | 5s | 8.2 | ebb | 0.2 | 41% | 33 | 6 |
| 9 PM | Heavy drizzle | 57° | ENE 12 | 13 | 1.5 | 5s | 7.2 | ebb | 0.5 | 50% | 16 | 6 |
| 10 PM | Heavy drizzle | 56° | NE 12 | 12 | 1.6 | 5s | 5.6 | ebb | 0.8 | 55% | 17 | 16 |
| 11 PM | Drizzle | 57° | NE 11 | 11 | 1.7 | 5s | 3.9 | ebb | 0.8 | 55% | 26 | 17 |
| 12 AMMon | Drizzle | 57° | NE 10 | 10 | 1.7 | 5s | 2.5 | ebb | 0.7 | 48% | 22 | 32 |
| 1 AM | Overcast | 56° | NNE 12 | 12 | 1.7 | 5s | 1.7 | ebb | 0.6 | 39% | 26 | 4 |
Sea in feet, period in seconds, tide in feet above mean lower low water, current in knots at the harbour entrance, visibility in miles, fog on a scale of one hundred.
From the Weather Service
The official word, printed as issued. Where this page disagrees with the bulletin, believe the bulletin.
Coastal Waters Forecast
National Weather Service · Gray, Maine
Zone ANZ153 — Casco Bay
National Weather Service · Gray, Maine
Zone ANZ153 — Casco Bay
Issued 5:02 PM EDT
.SYNOPSIS... Low pressure passes south of the waters Sunday into Sunday night bringing rain that may be heavy at times. Broad high pressure north of the Great Lakes then slowly makes its way east through midweek.
.Tonight... S winds 5 to 10 kt. Seas around 2 ft.
.Sun... S winds 5 to 10 kt with gusts up to 20 kt. Seas around 2 ft. Rain in the afternoon with vsby 1 to 3 NM.
.Sun Night... E winds 5 to 10 kt, becoming N with gusts up to 20 kt after midnight. Seas around 2 ft. Rain. Vsby 1 to 3 NM in the evening.
.Mon... N winds 10 to 15 kt with gusts up to 20 kt, diminishing to 5 to 10 kt in the afternoon. Seas around 2 ft.
.Mon Night... N winds 5 to 10 kt. Seas around 2 ft.
.Tue... NE winds 5 to 10 kt, becoming E in the afternoon. Seas around 2 ft.
.Tue Night... E winds around 5 kt, becoming NE with gusts up to 20 kt after midnight. Seas around 2 ft.
.Wed... NE winds 10 to 15 kt with gusts up to 20 kt. Seas around 2 ft.
Ashore
Overnight
Partly cloudy, with a low around 53. South wind around 5 mph.
Sunday
Rain likely between noon and 5pm, then rain and patchy fog. Mostly cloudy, with a high near 60. South wind 5 to 15 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch possible.
Sunday Night
Rain and patchy fog before 3am, then patchy fog and a slight chance of rain. Cloudy, with a low around 52. Northeast wind 5 to 15 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
Monday
Mostly sunny, with a high near 62. North wind 10 to 15 mph.
Monday Night
Partly cloudy, with a low around 50. North wind around 10 mph.
Tuesday
Mostly sunny, with a high near 58.
The Week Ahead
Wave heights run out past two and a half days — beyond that the marine model has nothing honest to say, and the column is left blank.
| Day | Weather | High | Low | Wind | Gust | Sea | Rain | Moon | High water |
|---|---|---|---|---|---|---|---|---|---|
| TodaySep 20 | Heavy drizzle | 59° | 52° | SE 13 | 16 | 1.7 | 55% | Waxing Gibbous67% | 6:56 AM · 7:06 PM |
| MonSep 21 | Rain | 62° | 51° | N 13 | 19 | 1.7 | 48% | Waxing Gibbous76% | 7:55 AM · 8:04 PM |
| TueSep 22 | Overcast | 61° | 46° | NE 7 | 19 | 1.9 | 0% | Waxing Gibbous83% | 8:47 AM · 8:56 PM |
| WedSep 23 | Overcast | 60° | 44° | NE 11 | 21 | — | 2% | Waxing Gibbous90% | 9:33 AM · 9:42 PM |
| ThuSep 24 | Overcast | 64° | 45° | NE 8 | 21 | — | 11% | Waxing Gibbous95% | 10:12 AM · 10:24 PM |
| FriSep 25 | Light rain | 67° | 48° | NNE 10 | 24 | — | 36% | Waxing Gibbous99% | 10:49 AM · 11:04 PM |
| SatSep 26 | Overcast | 57° | 53° | NNE 12 | 27 | — | 36% | Full Moon100% | 11:25 AM · 11:44 PM |
From the Buoys and Gauges
Measured, not modelled. These are the actual instruments in the water, with the age of each reading.
| Station | Distance | Wind | Sea | Per. | Swell | Water | Air | Age |
|---|---|---|---|---|---|---|---|---|
| Portland Harbour station 8418150, on the waterfront | — | SW 6 | — | — | — | 60.3° | 52.3° | 10m |
| Portland Lightship Buoy buoy 44007 — 12 nm southeast of portland — the bay's reference buoy | 10.5 nm | SSW 10 | 1.3 | 3s | 0.7 SE | 59.5° | 57.7° | 28m |
| Western Maine Shelf buoy 44030 — wind and air temperature on the western shelf | 33.5 nm | S 8 | — | — | — | 61.9° | 59.0° | 1h 28m |
| Jeffreys Ledge buoy 44098 — offshore to the south — shows swell arriving from the gulf | 54.2 nm | — | 1.0 | 7s | 0.3 E | 58.8° | 57.0° | 28m |
| Jonesport, Maine buoy 44027 — down east — early warning for weather tracking southwest | 128 nm | WNW 0 | 0.7 | 12s | 0.7 S | 53.1° | —° | 28m |
Freshwater into the bay
Presumpscot462 cfs
enters at Falmouth
Royal27 cfs
enters at Yarmouth
Androscoggin1,360 cfs
enters at Merrymeeting Bay
After rain the plume freshens and clouds the top few feet near the river mouths, and carries stormwater down with it for a day or two.
Air and sky
Air quality34
good
GeomagneticKp 2.3
no northern lights tonight
Casco Bay lies near 53° magnetic latitude. It takes Kp 6 or better before the lights clear the horizon, and you want to be off away from Portland’s glow — Chebeague, Cliff, or the north shore of Bailey.
Last reading 8:00 PM EDT