Grand Manan Island
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Grand Manan Island clear sky chart from 2005-11-06 to 2024-12-02.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	19% 10% 3 7% 4 4 4 3 5% 6% 34%	101625
	Night	21% 11% 4 8% 5% 4 4 3 5% 6% 30%	98051
Transparency	Day	50% 6% 12% 20% 11% 1	105172
	Night	54% 6% 11% 18% 10% 1	102594
Seeing	Day	24% 7% 22% 30% 15% 2	16405
	Night	26% 10% 25% 26% 11% 1	24411

By Month

Percentage Cloud Cover NE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	19% 11% 4 9% 5% 4 4 3 4 5% 32%	2283
	11th to 20th	Day	19% 11% 3 8% 4 4 3 2 4 4 38%	2520
	21st to end	Day	18% 11% 4 9% 8% 6% 5% 3 6% 6% 23%	3069
February	1st to 10th	Day	20% 13% 5% 7% 6% 4 5% 4 6% 6% 24%	1710
	11th to 20th	Day	17% 10% 3 8% 5% 8% 5% 5% 4 6% 28%	1663
	21st to end	Day	14% 12% 4 7% 5% 5% 4 4 6% 6% 33%	1565
March	1st to 10th	Day	25% 11% 4 7% 5% 5% 3 3 4 5% 29%	3275
	11th to 20th	Day	19% 10% 3 7% 5% 5% 4 4 5% 7% 31%	3480
	21st to end	Day	29% 11% 3 6% 3 4 4 3 4 4 28%	3816
April	1st to 10th	Day	22% 11% 3 7% 4 3 4 4 5% 6% 32%	2200
	11th to 20th	Day	20% 10% 2 6% 3 2 3 2 5% 7% 40%	2442
	21st to end	Day	21% 9% 2 6% 4 3 3 3 5% 6% 38%	2470
May	1st to 10th	Day	19% 10% 3 7% 4 4 4 3 5% 7% 32%	4106
	11th to 20th	Day	17% 7% 3 6% 5% 5% 4 3 5% 7% 38%	4174
	21st to end	Day	18% 9% 3 7% 4 4 4 4 6% 8% 33%	4890
June	1st to 10th	Day	23% 8% 3 7% 4 4 3 4 5% 7% 32%	2850
	11th to 20th	Day	21% 9% 3 5% 4 3 4 4 5% 7% 36%	2850
	21st to end	Day	26% 10% 4 6% 3 4 4 3 5% 6% 30%	2850
July	1st to 10th	Day	18% 12% 5% 8% 4 4 4 3 6% 7% 29%	4760
	11th to 20th	Day	19% 11% 4 7% 4 4 4 3 5% 8% 31%	4581
	21st to end	Day	18% 11% 3 6% 4 4 4 4 6% 8% 33%	4511
August	1st to 10th	Day	21% 13% 4 7% 4 4 4 4 4 6% 30%	4105
	11th to 20th	Day	15% 10% 3 7% 4 4 5% 3 5% 7% 36%	4045
	21st to end	Day	11% 6% 2 5% 3 3 4 3 5% 8% 51%	4532
September	1st to 10th	Day	12% 7% 2 6% 4 3 3 3 5% 7% 48%	2228
	11th to 20th	Day	16% 6% 2 4 3 3 3 2 4 6% 49%	2090
	21st to end	Day	18% 7% 2 5% 4 2 3 2 5% 7% 45%	2090
October	1st to 10th	Day	16% 7% 3 6% 4 4 4 3 5% 7% 42%	1954
	11th to 20th	Day	18% 6% 2 5% 4 3 4 4 5% 7% 42%	1900
	21st to end	Day	21% 8% 2 6% 3 4 5% 3 4 6% 38%	1977
November	1st to 10th	Day	20% 8% 4 7% 4 4 3 4 4 6% 37%	1761
	11th to 20th	Day	20% 8% 3 6% 3 3 3 4 5% 6% 38%	1602
	21st to end	Day	21% 12% 3 7% 5% 3 3 3 5% 6% 32%	1600
December	1st to 10th	Day	25% 10% 4 10% 6% 5% 4 3 4 5% 24%	1529
	11th to 20th	Day	25% 12% 4 11% 6% 4 4 4 5% 5% 20%	1716
	21st to end	Day	25% 10% 4 8% 5% 4 4 3 4 5% 27%	2431
January	1st to 10th	Night	17% 13% 4 8% 5% 5% 4 3 4 5% 31%	4652
	11th to 20th	Night	16% 14% 6% 11% 6% 5% 4 3 4 5% 27%	4440
	21st to end	Night	18% 12% 4 11% 6% 6% 5% 4 6% 5% 22%	4584
February	1st to 10th	Night	21% 10% 4 9% 6% 5% 4 3 5% 7% 25%	2470
	11th to 20th	Night	18% 12% 4 8% 6% 6% 4 4 6% 5% 27%	2403
	21st to end	Night	16% 10% 4 8% 6% 4 4 4 5% 5% 33%	1886
March	1st to 10th	Night	27% 13% 3 7% 4 5% 3 2 4 4 28%	3565
	11th to 20th	Night	17% 13% 4 8% 5% 5% 5% 4 6% 8% 25%	3479
	21st to end	Night	31% 9% 3 7% 4 5% 4 3 4 5% 26%	3816
April	1st to 10th	Night	24% 12% 2 6% 4 3 4 2 5% 5% 31%	1976
	11th to 20th	Night	23% 10% 3 6% 4 4 4 3 6% 6% 32%	1688
	21st to end	Night	27% 8% 3 6% 4 4 3 3 5% 6% 30%	1710
May	1st to 10th	Night	22% 9% 4 7% 4 3 3 3 5% 6% 33%	2834
	11th to 20th	Night	19% 7% 3 7% 5% 6% 4 4 6% 7% 32%	2721
	21st to end	Night	18% 11% 4 8% 5% 4 4 4 6% 7% 30%	2722
June	1st to 10th	Night	26% 10% 3 7% 6% 4 3 4 5% 7% 26%	1330
	11th to 20th	Night	22% 10% 3 7% 5% 3 4 3 5% 5% 34%	1330
	21st to end	Night	29% 11% 3 7% 5% 3 3 3 5% 6% 26%	1330
July	1st to 10th	Night	20% 17% 5% 9% 4 4 4 4 5% 6% 21%	2210
	11th to 20th	Night	21% 13% 4 7% 4 4 4 4 5% 6% 26%	2380
	21st to end	Night	16% 13% 4 8% 4 4 4 3 5% 7% 31%	3010
August	1st to 10th	Night	22% 16% 5% 8% 4 3 4 3 5% 7% 24%	2825
	11th to 20th	Night	15% 13% 5% 7% 5% 5% 5% 3 5% 8% 28%	2782
	21st to end	Night	11% 10% 4 8% 4 4 4 2 5% 6% 44%	3124
September	1st to 10th	Night	15% 9% 3 5% 3 4 3 3 4 8% 43%	1950
	11th to 20th	Night	17% 8% 2 5% 4 4 3 3 4 6% 45%	2090
	21st to end	Night	19% 7% 2 6% 4 3 3 3 4 7% 42%	2090
October	1st to 10th	Night	18% 6% 2 6% 4 3 5% 3 4 7% 41%	2225
	11th to 20th	Night	17% 8% 2 6% 4 4 4 3 5% 7% 40%	2280
	21st to end	Night	23% 10% 3 6% 3 4 3 3 4 5% 36%	2617
November	1st to 10th	Night	20% 8% 2 5% 5% 4 4 4 5% 6% 37%	2537
	11th to 20th	Night	19% 10% 3 6% 5% 4 4 4 5% 7% 34%	2796
	21st to end	Night	21% 11% 3 7% 5% 4 5% 4 5% 6% 29%	2800
December	1st to 10th	Night	27% 13% 4 9% 5% 4 4 3 5% 5% 22%	2685
	11th to 20th	Night	27% 12% 3 8% 6% 5% 4 4 5% 5% 21%	3478
	21st to end	Night	24% 12% 4 6% 4 4 4 3 4 5% 28%	5236

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	56% 6% 18% 15% 4	2284
	11th to 20th	Day	54% 4 10% 21% 10% 1	2520
	21st to end	Day	63% 6% 14% 12% 4	3069
February	1st to 10th	Day	61% 7% 12% 14% 6%	1710
	11th to 20th	Day	59% 7% 11% 16% 7%	1671
	21st to end	Day	51% 6% 13% 19% 8% 3	1565
March	1st to 10th	Day	58% 5% 10% 15% 8% 3	3279
	11th to 20th	Day	49% 8% 15% 16% 10% 1	3480
	21st to end	Day	58% 4 7% 15% 13% 2	3816
April	1st to 10th	Day	52% 5% 9% 17% 15% 3	2200
	11th to 20th	Day	44% 4 11% 24% 14% 2	2442
	21st to end	Day	47% 5% 9% 22% 16% 2	2470
May	1st to 10th	Day	49% 7% 15% 19% 8% 1	4120
	11th to 20th	Day	45% 8% 16% 22% 9% 1	4178
	21st to end	Day	48% 8% 15% 17% 12% 1	4890
June	1st to 10th	Day	53% 5% 11% 21% 9% 1	2850
	11th to 20th	Day	48% 5% 11% 19% 14% 2	2850
	21st to end	Day	57% 6% 10% 16% 10% 1	2850
July	1st to 10th	Day	56% 7% 9% 16% 11%	4685
	11th to 20th	Day	54% 6% 11% 20% 9%	4501
	21st to end	Day	49% 6% 15% 20% 9%	4367
August	1st to 10th	Day	56% 7% 9% 19% 8%	4092
	11th to 20th	Day	49% 6% 17% 20% 9%	4084
	21st to end	Day	33% 6% 12% 27% 22% 1	4532
September	1st to 10th	Day	38% 5% 12% 26% 18% 1	2228
	11th to 20th	Day	37% 5% 11% 27% 18% 3	2090
	21st to end	Day	41% 4 10% 29% 16% 1	2090
October	1st to 10th	Day	45% 6% 11% 27% 11%	3240
	11th to 20th	Day	32% 3 11% 36% 17%	3140
	21st to end	Day	38% 4 17% 24% 15% 2	3240
November	1st to 10th	Day	50% 5% 12% 21% 11% 1	1761
	11th to 20th	Day	48% 6% 13% 22% 10% 2	1602
	21st to end	Day	56% 5% 15% 18% 6%	1600
December	1st to 10th	Day	64% 7% 11% 14% 4 1	1529
	11th to 20th	Day	68% 6% 8% 12% 5%	1716
	21st to end	Day	61% 7% 11% 13% 7% 1	2431
January	1st to 10th	Night	56% 9% 12% 19% 4	4652
	11th to 20th	Night	61% 6% 10% 15% 7% 1	4440
	21st to end	Night	66% 6% 12% 13% 3	4584
February	1st to 10th	Night	62% 6% 11% 13% 7% 1	2470
	11th to 20th	Night	60% 7% 8% 16% 8% 1	2406
	21st to end	Night	55% 6% 11% 17% 10% 2	1886
March	1st to 10th	Night	61% 5% 9% 14% 10% 1	3574
	11th to 20th	Night	54% 8% 14% 14% 9% 1	3480
	21st to end	Night	61% 4 7% 16% 10% 2	3816
April	1st to 10th	Night	55% 5% 8% 15% 14% 3	1976
	11th to 20th	Night	51% 5% 10% 20% 13% 1	1688
	21st to end	Night	54% 4 8% 17% 14% 2	1710
May	1st to 10th	Night	51% 6% 16% 18% 8% 1	2840
	11th to 20th	Night	50% 8% 16% 19% 7% 1	2722
	21st to end	Night	52% 7% 14% 20% 7% 1	2723
June	1st to 10th	Night	58% 6% 9% 19% 7% 1	1330
	11th to 20th	Night	52% 5% 9% 21% 10% 2	1330
	21st to end	Night	60% 6% 7% 17% 7% 3	1330
July	1st to 10th	Night	62% 6% 8% 13% 10%	2175
	11th to 20th	Night	57% 6% 10% 17% 9%	2337
	21st to end	Night	51% 6% 10% 20% 12% 1	2914
August	1st to 10th	Night	61% 5% 9% 19% 6%	2813
	11th to 20th	Night	54% 6% 14% 19% 7%	2809
	21st to end	Night	41% 5% 8% 27% 17% 2	3124
September	1st to 10th	Night	40% 6% 10% 27% 17% 1	1950
	11th to 20th	Night	41% 4 10% 26% 18% 2	2090
	21st to end	Night	43% 4 8% 26% 17% 1	2090
October	1st to 10th	Night	43% 5% 13% 26% 13% 1	3719
	11th to 20th	Night	35% 5% 12% 27% 21%	3779
	21st to end	Night	43% 4 10% 26% 15% 2	4304
November	1st to 10th	Night	48% 6% 14% 20% 11% 1	2537
	11th to 20th	Night	51% 7% 12% 18% 12% 1	2796
	21st to end	Night	57% 6% 14% 17% 6% 1	2800
December	1st to 10th	Night	67% 5% 10% 13% 5%	2685
	11th to 20th	Night	65% 6% 10% 13% 5% 1	3479
	21st to end	Night	58% 7% 13% 15% 6% 1	5236

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	33% 11% 33% 16% 6% 1	180
	11th to 20th	Day	29% 14% 33% 18% 6%	180
	21st to end	Day	24% 12% 38% 22% 5% 1	378
February	1st to 10th	Day	27% 14% 33% 19% 6%	370
	11th to 20th	Day	26% 14% 36% 21% 3	366
	21st to end	Day	20% 14% 31% 27% 8%	379
March	1st to 10th	Day	21% 13% 36% 24% 6%	460
	11th to 20th	Day	20% 15% 30% 24% 10% 1	460
	21st to end	Day	25% 9% 31% 24% 9% 1	506
April	1st to 10th	Day	28% 11% 27% 28% 5% 1	460
	11th to 20th	Day	23% 6% 29% 29% 12% 1	452
	21st to end	Day	24% 5% 26% 31% 12% 2	460
May	1st to 10th	Day	25% 4 25% 34% 10% 2	463
	11th to 20th	Day	23% 2 19% 36% 19% 1	541
	21st to end	Day	28% 3 19% 35% 13% 2	735
June	1st to 10th	Day	25% 4 17% 37% 15% 3	680
	11th to 20th	Day	23% 3 14% 34% 22% 3	680
	21st to end	Day	33% 2 13% 32% 15% 5%	680
July	1st to 10th	Day	26% 2 11% 37% 21% 3	670
	11th to 20th	Day	24% 3 7% 35% 27% 4	568
	21st to end	Day	20% 3 12% 37% 25% 4	532
August	1st to 10th	Day	18% 4 9% 35% 28% 6%	486
	11th to 20th	Day	24% 3 8% 35% 25% 5%	479
	21st to end	Day	19% 2 12% 34% 27% 6%	539
September	1st to 10th	Day	18% 2 13% 41% 23% 3	490
	11th to 20th	Day	22% 3 17% 29% 24% 5%	490
	21st to end	Day	19% 2 18% 36% 19% 6%	490
October	1st to 10th	Day	18% 6% 21% 33% 18% 4	417
	11th to 20th	Day	19% 5% 27% 29% 16% 3	390
	21st to end	Day	24% 10% 26% 28% 10% 2	429
November	1st to 10th	Day	25% 12% 26% 26% 10% 2	395
	11th to 20th	Day	26% 15% 32% 20% 8%	400
	21st to end	Day	30% 15% 31% 20% 5% 1	400
December	1st to 10th	Day	32% 10% 33% 20% 5%	374
	11th to 20th	Day	33% 13% 34% 17% 3	228
	21st to end	Day	26% 12% 39% 17% 4 2	198
January	1st to 10th	Night	30% 17% 30% 18% 4	823
	11th to 20th	Night	29% 17% 32% 17% 5%	760
	21st to end	Night	23% 17% 36% 20% 4	836
February	1st to 10th	Night	27% 19% 31% 19% 4	760
	11th to 20th	Night	25% 20% 33% 18% 3 1	743
	21st to end	Night	20% 17% 32% 25% 5%	628
March	1st to 10th	Night	25% 14% 36% 23% 3	760
	11th to 20th	Night	24% 13% 30% 26% 8%	760
	21st to end	Night	24% 11% 31% 25% 8% 1	836
April	1st to 10th	Night	29% 10% 31% 23% 6%	698
	11th to 20th	Night	25% 6% 30% 30% 9% 1	564
	21st to end	Night	30% 3 27% 27% 11% 2	570
May	1st to 10th	Night	27% 3 24% 32% 11% 2	570
	11th to 20th	Night	29% 4 20% 34% 12% 1	562
	21st to end	Night	25% 2 20% 36% 14% 2	602
June	1st to 10th	Night	30% 4 17% 32% 15% 1	380
	11th to 20th	Night	26% 3 14% 36% 19% 1	380
	21st to end	Night	33% 2 9% 37% 16% 3	380
July	1st to 10th	Night	28% 3 9% 35% 24% 1	370
	11th to 20th	Night	28% 2 9% 37% 22% 3	368
	21st to end	Night	28% 2 8% 38% 23% 2	572
August	1st to 10th	Night	19% 3 9% 40% 27% 2	568
	11th to 20th	Night	25% 3 10% 33% 26% 2	562
	21st to end	Night	18% 2 11% 39% 25% 5%	627
September	1st to 10th	Night	20% 3 14% 40% 21% 3	634
	11th to 20th	Night	21% 4 17% 29% 24% 5%	760
	21st to end	Night	23% 3 19% 31% 19% 5%	760
October	1st to 10th	Night	23% 4 19% 32% 18% 3	760
	11th to 20th	Night	19% 8% 28% 27% 15% 3	760
	21st to end	Night	29% 11% 28% 23% 8%	836
November	1st to 10th	Night	25% 10% 30% 24% 9% 1	780
	11th to 20th	Night	24% 15% 32% 19% 9%	898
	21st to end	Night	28% 16% 29% 19% 7% 1	900
December	1st to 10th	Night	35% 13% 31% 18% 3	859
	11th to 20th	Night	31% 19% 32% 14% 3	850
	21st to end	Night	30% 19% 29% 17% 4 1	935

Page generated at 2024-11-29 11:43:09. Version ac07

Copyright © 2024 Attilla Danko.