Peawanuck
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Peawanuck clear sky chart from 2005-11-06 to 2024-02-05.

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	16% 12% 5% 9% 8% 4 6% 6% 6% 6% 21%	77388
	Night	12% 13% 6% 11% 9% 5% 7% 7% 6% 6% 17%	81514
Transparency	Day	61% 8% 11% 15% 5%	77058
	Night	63% 8% 11% 13% 4	81378
Seeing	Day	21% 8% 26% 27% 14% 4	14544
	Night	19% 7% 27% 31% 14% 3	23812

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	8% 12% 4 14% 11% 7% 12% 10% 10% 6% 5%	1899
	11th to 20th	Day	4 12% 8% 15% 14% 6% 12% 9% 9% 5% 5%	1998
	21st to end	Day	10% 17% 7% 12% 10% 5% 7% 8% 10% 7% 6%	2627
February	1st to 10th	Day	5% 9% 5% 9% 11% 7% 14% 11% 11% 9% 9%	1472
	11th to 20th	Day	3 8% 4 10% 10% 5% 14% 12% 11% 9% 15%	1430
	21st to end	Day	3 8% 5% 8% 8% 5% 8% 16% 13% 8% 20%	1440
March	1st to 10th	Day	5% 9% 5% 10% 11% 5% 9% 12% 10% 8% 15%	1798
	11th to 20th	Day	6% 9% 4 9% 10% 7% 10% 11% 9% 8% 17%	1895
	21st to end	Day	10% 10% 4 8% 8% 6% 9% 10% 7% 7% 21%	2305
April	1st to 10th	Day	11% 11% 5% 9% 10% 8% 10% 7% 5% 6% 19%	2207
	11th to 20th	Day	8% 10% 5% 12% 11% 6% 7% 5% 4 6% 27%	2312
	21st to end	Day	13% 13% 5% 10% 10% 4 4 4 5% 5% 29%	2432
May	1st to 10th	Day	15% 13% 6% 13% 8% 3 4 5% 4 6% 23%	2640
	11th to 20th	Day	15% 13% 6% 10% 8% 3 5% 5% 5% 6% 24%	2656
	21st to end	Day	17% 13% 7% 10% 6% 4 4 5% 4 6% 23%	2948
June	1st to 10th	Day	15% 11% 4 7% 6% 3 5% 5% 6% 7% 31%	2880
	11th to 20th	Day	19% 7% 3 5% 6% 4 4 5% 5% 7% 34%	2880
	21st to end	Day	21% 8% 4 6% 5% 3 4 5% 5% 6% 35%	2880
July	1st to 10th	Day	20% 8% 3 6% 6% 3 6% 5% 6% 8% 30%	2880
	11th to 20th	Day	19% 9% 4 5% 5% 4 5% 5% 6% 7% 32%	2880
	21st to end	Day	21% 10% 4 7% 6% 4 4 5% 5% 7% 26%	2940
August	1st to 10th	Day	28% 11% 3 6% 5% 3 4 6% 4 6% 24%	2561
	11th to 20th	Day	24% 10% 4 8% 6% 3 5% 5% 5% 7% 24%	2476
	21st to end	Day	22% 11% 3 8% 6% 4 5% 5% 6% 6% 26%	2574
September	1st to 10th	Day	27% 13% 4 8% 6% 3 5% 5% 4 6% 19%	2242
	11th to 20th	Day	28% 14% 5% 7% 6% 3 4 4 4 4 20%	2020
	21st to end	Day	24% 18% 3 7% 5% 2 3 4 4 5% 24%	1980
October	1st to 10th	Day	26% 22% 5% 7% 6% 3 3 4 3 5% 15%	1840
	11th to 20th	Day	22% 24% 6% 8% 6% 3 4 4 4 4 13%	1620
	21st to end	Day	21% 21% 7% 10% 8% 4 5% 4 4 4 13%	1782
November	1st to 10th	Day	19% 20% 6% 10% 8% 5% 6% 5% 5% 6% 11%	1401
	11th to 20th	Day	14% 18% 10% 12% 10% 5% 6% 3 3 4 13%	1330
	21st to end	Day	12% 17% 8% 14% 9% 5% 8% 6% 5% 5% 11%	1330
December	1st to 10th	Day	9% 14% 7% 14% 13% 6% 7% 6% 7% 6% 11%	1307
	11th to 20th	Day	5% 11% 7% 12% 12% 10% 9% 7% 7% 5% 14%	1436
	21st to end	Day	8% 13% 7% 14% 13% 7% 8% 6% 5% 6% 13%	2090
January	1st to 10th	Night	6% 10% 5% 16% 15% 9% 12% 9% 7% 6% 4	5057
	11th to 20th	Night	4 12% 8% 19% 13% 7% 11% 9% 8% 5% 5%	4970
	21st to end	Night	5% 15% 7% 14% 12% 5% 9% 9% 8% 7% 9%	5040
February	1st to 10th	Night	3 8% 5% 10% 13% 8% 13% 13% 10% 6% 10%	2583
	11th to 20th	Night	4 8% 4 10% 11% 7% 12% 12% 12% 8% 13%	2416
	21st to end	Night	3 8% 4 7% 9% 4 10% 15% 12% 9% 18%	1815
March	1st to 10th	Night	5% 7% 4 12% 8% 7% 11% 10% 10% 8% 17%	2149
	11th to 20th	Night	7% 10% 4 9% 9% 6% 10% 9% 8% 8% 20%	2064
	21st to end	Night	9% 8% 5% 9% 8% 6% 7% 8% 8% 9% 24%	2066
April	1st to 10th	Night	12% 11% 4 9% 8% 5% 7% 6% 5% 6% 26%	1753
	11th to 20th	Night	10% 11% 5% 9% 9% 5% 6% 5% 4 6% 30%	1597
	21st to end	Night	12% 11% 5% 8% 8% 4 4 4 3 6% 33%	1526
May	1st to 10th	Night	16% 15% 5% 12% 8% 3 4 3 4 3 26%	1319
	11th to 20th	Night	15% 9% 6% 11% 8% 3 4 5% 6% 7% 26%	1239
	21st to end	Night	19% 13% 9% 11% 7% 3 4 4 4 4 22%	1326
June	1st to 10th	Night	18% 10% 5% 7% 8% 3 5% 4 5% 7% 29%	1080
	11th to 20th	Night	17% 9% 3 6% 6% 3 4 6% 5% 9% 33%	1080
	21st to end	Night	17% 8% 4 7% 6% 3 4 3 5% 6% 37%	1080
July	1st to 10th	Night	16% 8% 4 7% 7% 4 6% 6% 5% 6% 29%	1080
	11th to 20th	Night	18% 10% 3 6% 6% 3 5% 5% 5% 8% 31%	1080
	21st to end	Night	20% 10% 5% 8% 6% 3 4 4 5% 7% 30%	1378
August	1st to 10th	Night	23% 11% 3 6% 6% 3 4 5% 6% 7% 26%	1377
	11th to 20th	Night	24% 10% 3 7% 6% 4 4 4 4 7% 27%	1424
	21st to end	Night	21% 10% 3 7% 6% 4 5% 5% 6% 6% 28%	1782
September	1st to 10th	Night	20% 11% 4 7% 6% 3 5% 4 5% 7% 27%	1715
	11th to 20th	Night	27% 16% 3 6% 6% 3 3 3 4 6% 24%	1922
	21st to end	Night	21% 16% 4 7% 5% 4 4 4 4 6% 25%	1980
October	1st to 10th	Night	26% 20% 4 8% 4 3 5% 4 4 5% 18%	2117
	11th to 20th	Night	23% 22% 5% 8% 6% 3 5% 4 4 4 14%	2340
	21st to end	Night	19% 20% 6% 10% 6% 3 4 4 4 6% 17%	2574
November	1st to 10th	Night	21% 20% 8% 10% 6% 4 5% 4 4 5% 14%	2676
	11th to 20th	Night	13% 20% 7% 14% 10% 4 6% 4 4 5% 12%	2850
	21st to end	Night	12% 20% 10% 14% 9% 4 6% 4 4 4 12%	2850
December	1st to 10th	Night	9% 16% 9% 14% 11% 5% 7% 6% 7% 6% 10%	2871
	11th to 20th	Night	6% 13% 7% 13% 12% 7% 8% 9% 6% 6% 13%	3761
	21st to end	Night	8% 14% 7% 11% 10% 8% 8% 7% 6% 6% 16%	5577

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	70% 9% 9% 7% 4	1900
	11th to 20th	Day	72% 8% 9% 8% 3	1998
	21st to end	Day	69% 6% 8% 10% 8%	2627
February	1st to 10th	Day	60% 8% 12% 14% 6%	1472
	11th to 20th	Day	55% 7% 15% 18% 5%	1438
	21st to end	Day	46% 8% 12% 22% 11%	1440
March	1st to 10th	Day	56% 10% 10% 17% 7%	1800
	11th to 20th	Day	58% 7% 11% 16% 7% 1	1895
	21st to end	Day	57% 8% 10% 18% 7% 1	2305
April	1st to 10th	Day	63% 8% 7% 14% 8%	2207
	11th to 20th	Day	58% 6% 9% 18% 9% 1	2312
	21st to end	Day	58% 6% 7% 19% 10%	2432
May	1st to 10th	Day	62% 6% 10% 17% 6%	2640
	11th to 20th	Day	60% 8% 11% 16% 6%	2660
	21st to end	Day	61% 7% 10% 17% 5%	2948
June	1st to 10th	Day	50% 9% 12% 20% 9%	2880
	11th to 20th	Day	49% 7% 12% 24% 8%	2880
	21st to end	Day	49% 6% 11% 23% 9%	2880
July	1st to 10th	Day	50% 9% 17% 20% 3	2801
	11th to 20th	Day	49% 10% 16% 20% 4	2793
	21st to end	Day	56% 11% 16% 15% 2	2777
August	1st to 10th	Day	58% 11% 13% 15% 2	2545
	11th to 20th	Day	58% 10% 15% 15% 2	2476
	21st to end	Day	58% 9% 15% 15% 4	2574
September	1st to 10th	Day	65% 8% 12% 11% 3	2242
	11th to 20th	Day	67% 6% 12% 12% 2	2020
	21st to end	Day	63% 6% 12% 14% 5%	1980
October	1st to 10th	Day	72% 6% 10% 9% 2	1840
	11th to 20th	Day	74% 7% 12% 6% 1	1620
	21st to end	Day	76% 7% 8% 7% 2	1782
November	1st to 10th	Day	73% 9% 10% 6% 1	1401
	11th to 20th	Day	77% 7% 10% 5% 2	1330
	21st to end	Day	73% 8% 11% 8% 1	1330
December	1st to 10th	Day	69% 8% 11% 9% 3	1307
	11th to 20th	Day	64% 8% 10% 12% 6%	1436
	21st to end	Day	69% 7% 7% 13% 4	2090
January	1st to 10th	Night	75% 8% 10% 7% 1	5057
	11th to 20th	Night	74% 8% 9% 7% 2	4970
	21st to end	Night	68% 7% 8% 12% 5%	5040
February	1st to 10th	Night	62% 9% 11% 13% 6%	2583
	11th to 20th	Night	57% 9% 11% 17% 5%	2418
	21st to end	Night	49% 7% 14% 19% 10%	1815
March	1st to 10th	Night	54% 8% 11% 19% 6% 1	2160
	11th to 20th	Night	56% 7% 12% 18% 7%	2065
	21st to end	Night	52% 8% 10% 21% 9% 1	2066
April	1st to 10th	Night	56% 6% 9% 18% 10% 1	1753
	11th to 20th	Night	55% 5% 10% 19% 11% 1	1597
	21st to end	Night	51% 7% 7% 22% 13%	1526
May	1st to 10th	Night	62% 6% 7% 17% 8% 1	1319
	11th to 20th	Night	55% 8% 12% 16% 8% 1	1240
	21st to end	Night	65% 7% 10% 12% 7%	1327
June	1st to 10th	Night	55% 6% 11% 18% 9% 1	1080
	11th to 20th	Night	48% 8% 14% 19% 10%	1080
	21st to end	Night	48% 7% 13% 24% 9%	1080
July	1st to 10th	Night	53% 9% 14% 20% 5%	1050
	11th to 20th	Night	49% 9% 17% 21% 3	1044
	21st to end	Night	54% 9% 16% 16% 4	1301
August	1st to 10th	Night	56% 10% 17% 15% 2	1369
	11th to 20th	Night	57% 8% 15% 16% 4	1424
	21st to end	Night	54% 10% 15% 16% 3 1	1782
September	1st to 10th	Night	55% 12% 17% 13% 2	1715
	11th to 20th	Night	62% 8% 13% 16% 1	1922
	21st to end	Night	61% 7% 12% 16% 3	1980
October	1st to 10th	Night	69% 8% 10% 11% 2	2117
	11th to 20th	Night	72% 7% 12% 7% 1	2340
	21st to end	Night	70% 8% 11% 9% 3	2574
November	1st to 10th	Night	73% 7% 10% 7% 2	2676
	11th to 20th	Night	73% 8% 11% 7% 1	2850
	21st to end	Night	74% 6% 9% 9% 1	2850
December	1st to 10th	Night	71% 7% 11% 10% 2	2871
	11th to 20th	Night	64% 10% 11% 11% 4	3760
	21st to end	Night	65% 6% 10% 13% 5%	5577

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	9% 6% 32% 33% 18% 2	180
	11th to 20th	Day	8% 4 33% 35% 13% 6%	180
	21st to end	Day	14% 5% 22% 31% 18% 10%	254
February	1st to 10th	Day	6% 3 27% 37% 24% 3	252
	11th to 20th	Day	3 10% 30% 38% 16% 3	240
	21st to end	Day	7% 4 36% 28% 19% 7%	198
March	1st to 10th	Day	7% 5% 24% 33% 16% 15%	240
	11th to 20th	Day	7% 7% 31% 36% 15% 4	335
	21st to end	Day	14% 9% 27% 27% 16% 7%	462
April	1st to 10th	Day	15% 5% 24% 32% 19% 6%	420
	11th to 20th	Day	12% 8% 25% 33% 16% 6%	412
	21st to end	Day	19% 6% 26% 29% 16% 4	512
May	1st to 10th	Day	21% 8% 28% 24% 13% 5%	603
	11th to 20th	Day	19% 11% 30% 29% 10% 2	625
	21st to end	Day	24% 11% 32% 23% 9% 1	679
June	1st to 10th	Day	21% 7% 29% 27% 13% 4	630
	11th to 20th	Day	22% 6% 28% 26% 14% 3	630
	21st to end	Day	23% 8% 26% 26% 12% 5%	630
July	1st to 10th	Day	22% 6% 22% 31% 15% 4	621
	11th to 20th	Day	20% 6% 28% 28% 14% 3	618
	21st to end	Day	26% 5% 20% 27% 16% 6%	684
August	1st to 10th	Day	32% 6% 19% 23% 15% 5%	626
	11th to 20th	Day	25% 8% 21% 24% 14% 7%	612
	21st to end	Day	29% 7% 18% 29% 13% 6%	495
September	1st to 10th	Day	32% 9% 25% 22% 10% 2	450
	11th to 20th	Day	32% 9% 21% 24% 10% 3	450
	21st to end	Day	32% 10% 26% 17% 11% 3	450
October	1st to 10th	Day	29% 13% 30% 17% 9% 2	388
	11th to 20th	Day	29% 13% 24% 22% 9% 3	270
	21st to end	Day	23% 13% 26% 26% 10% 2	297
November	1st to 10th	Day	21% 16% 23% 24% 11% 4	183
	11th to 20th	Day	17% 12% 25% 29% 16% 2	180
	21st to end	Day	15% 8% 36% 23% 16% 2	180
December	1st to 10th	Day	14% 8% 32% 33% 12% 2	180
	11th to 20th	Day	13% 7% 28% 32% 16% 4	180
	21st to end	Day	11% 5% 27% 30% 19% 8%	198
January	1st to 10th	Night	13% 5% 30% 34% 14% 3	950
	11th to 20th	Night	11% 6% 27% 38% 14% 4	950
	21st to end	Night	10% 4 25% 35% 20% 6%	1045
February	1st to 10th	Night	5% 5% 29% 37% 21% 4	923
	11th to 20th	Night	8% 4 28% 37% 18% 5%	847
	21st to end	Night	6% 5% 26% 34% 22% 8%	592
March	1st to 10th	Night	8% 5% 23% 36% 23% 5%	720
	11th to 20th	Night	10% 6% 36% 33% 14% 1	720
	21st to end	Night	13% 8% 26% 32% 19% 4	680
April	1st to 10th	Night	17% 5% 21% 38% 16% 3	540
	11th to 20th	Night	13% 5% 27% 32% 20% 3	533
	21st to end	Night	16% 5% 25% 35% 17% 1	540
May	1st to 10th	Night	24% 6% 26% 30% 13% 1	419
	11th to 20th	Night	16% 8% 38% 30% 8%	354
	21st to end	Night	23% 11% 34% 26% 5%	389
June	1st to 10th	Night	21% 8% 31% 29% 11% 1	360
	11th to 20th	Night	21% 6% 32% 32% 9% 1	360
	21st to end	Night	21% 6% 26% 38% 10%	360
July	1st to 10th	Night	19% 5% 26% 36% 13%	350
	11th to 20th	Night	20% 5% 26% 36% 12% 1	348
	21st to end	Night	25% 4 20% 37% 13% 1	394
August	1st to 10th	Night	29% 3 21% 32% 14% 1	482
	11th to 20th	Night	27% 3 25% 30% 15% 1	534
	21st to end	Night	25% 6% 24% 32% 12% 1	594
September	1st to 10th	Night	25% 6% 29% 27% 11% 1	540
	11th to 20th	Night	34% 7% 26% 23% 9%	662
	21st to end	Night	30% 8% 28% 25% 8% 1	720
October	1st to 10th	Night	37% 10% 26% 20% 6% 1	720
	11th to 20th	Night	35% 8% 23% 22% 11% 1	720
	21st to end	Night	27% 7% 26% 24% 12% 3	792
November	1st to 10th	Night	30% 9% 22% 25% 12% 2	829
	11th to 20th	Night	21% 10% 31% 25% 11% 2	950
	21st to end	Night	22% 10% 30% 26% 10% 1	950
December	1st to 10th	Night	15% 10% 31% 33% 9% 2	950
	11th to 20th	Night	11% 6% 27% 35% 18% 3	950
	21st to end	Night	14% 6% 27% 32% 16% 5%	1045

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