Nipigon
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Nipigon 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	15% 9% 4 7% 6% 4 5% 5% 6% 7% 32%	77843
	Night	14% 11% 5% 8% 7% 4 5% 5% 5% 7% 29%	81049
Transparency	Day	34% 38% 9% 14% 5% 1	77548
	Night	38% 36% 9% 13% 5%	80878
Seeing	Day	18% 17% 35% 21% 8% 2	14738
	Night	19% 11% 31% 29% 10% 1	24502

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	12% 11% 5% 9% 10% 6% 7% 7% 7% 8% 18%	2527
	11th to 20th	Day	6% 9% 5% 12% 10% 6% 7% 7% 8% 7% 23%	2530
	21st to end	Day	13% 16% 10% 9% 7% 4 6% 5% 6% 7% 15%	2783
February	1st to 10th	Day	7% 11% 4 8% 7% 3 6% 7% 8% 8% 31%	1494
	11th to 20th	Day	8% 10% 4 9% 8% 4 5% 5% 7% 8% 32%	1619
	21st to end	Day	6% 9% 5% 9% 8% 5% 6% 5% 7% 8% 32%	1480
March	1st to 10th	Day	9% 10% 6% 9% 7% 3 5% 3 5% 6% 37%	1798
	11th to 20th	Day	13% 10% 4 7% 6% 4 5% 5% 5% 6% 35%	1851
	21st to end	Day	14% 9% 3 6% 6% 4 6% 4 5% 7% 36%	2376
April	1st to 10th	Day	15% 10% 3 7% 6% 4 5% 6% 5% 6% 33%	2160
	11th to 20th	Day	17% 11% 4 7% 5% 4 4 5% 5% 7% 31%	2181
	21st to end	Day	16% 11% 4 6% 5% 3 5% 4 5% 7% 35%	2376
May	1st to 10th	Day	18% 9% 4 7% 6% 4 5% 5% 6% 7% 30%	2520
	11th to 20th	Day	16% 8% 3 5% 5% 3 4 5% 5% 7% 38%	2479
	21st to end	Day	18% 7% 3 5% 5% 3 4 4 5% 8% 37%	2772
June	1st to 10th	Day	18% 6% 2 5% 5% 3 6% 5% 6% 8% 36%	2700
	11th to 20th	Day	14% 6% 3 5% 5% 3 4 6% 6% 8% 40%	2700
	21st to end	Day	17% 6% 3 6% 5% 4 5% 4 6% 8% 37%	2700
July	1st to 10th	Day	10% 5% 3 5% 4 3 5% 5% 7% 9% 44%	2595
	11th to 20th	Day	11% 5% 3 6% 6% 3 5% 5% 6% 8% 41%	2520
	21st to end	Day	12% 6% 3 4 6% 3 5% 6% 6% 9% 40%	2743
August	1st to 10th	Day	9% 6% 3 6% 6% 4 6% 7% 8% 9% 37%	2507
	11th to 20th	Day	14% 5% 2 4 5% 3 5% 5% 5% 9% 44%	2443
	21st to end	Day	16% 7% 2 5% 5% 3 4 4 6% 7% 40%	2412
September	1st to 10th	Day	14% 6% 3 6% 6% 3 5% 5% 5% 8% 41%	2160
	11th to 20th	Day	19% 7% 3 5% 6% 3 4 5% 5% 9% 35%	2080
	21st to end	Day	18% 9% 4 7% 6% 3 4 4 6% 7% 32%	1980
October	1st to 10th	Day	22% 13% 4 7% 5% 3 4 5% 4 8% 26%	1854
	11th to 20th	Day	21% 11% 5% 9% 8% 5% 5% 5% 5% 7% 20%	1694
	21st to end	Day	21% 14% 5% 10% 7% 4 5% 5% 4 6% 20%	1782
November	1st to 10th	Day	18% 11% 6% 8% 8% 4 4 5% 6% 7% 22%	1672
	11th to 20th	Day	20% 15% 6% 11% 8% 3 4 4 6% 5% 18%	1522
	21st to end	Day	17% 13% 7% 9% 9% 6% 7% 4 5% 5% 17%	1365
December	1st to 10th	Day	12% 10% 6% 12% 10% 4 7% 5% 6% 8% 21%	1330
	11th to 20th	Day	12% 13% 5% 10% 9% 4 7% 5% 7% 7% 21%	1671
	21st to end	Day	23% 21% 5% 8% 5% 2 4 4 5% 6% 17%	2467
January	1st to 10th	Night	9% 14% 5% 9% 9% 5% 7% 6% 6% 9% 21%	4428
	11th to 20th	Night	6% 8% 5% 15% 13% 6% 9% 7% 6% 6% 18%	4440
	21st to end	Night	10% 16% 9% 10% 9% 5% 6% 6% 5% 6% 18%	4884
February	1st to 10th	Night	8% 10% 5% 8% 7% 5% 8% 7% 6% 8% 28%	2561
	11th to 20th	Night	10% 10% 4 7% 7% 5% 7% 7% 7% 7% 30%	2228
	21st to end	Night	6% 12% 7% 11% 7% 4 5% 6% 5% 6% 31%	1776
March	1st to 10th	Night	8% 9% 4 9% 7% 4 6% 5% 6% 8% 35%	2149
	11th to 20th	Night	12% 11% 4 8% 6% 3 5% 4 4 6% 37%	2121
	21st to end	Night	13% 8% 4 5% 6% 4 4 6% 5% 7% 39%	1980
April	1st to 10th	Night	15% 10% 5% 7% 7% 4 5% 5% 6% 6% 30%	1800
	11th to 20th	Night	17% 10% 4 6% 5% 3 4 5% 6% 7% 33%	1728
	21st to end	Night	16% 9% 3 6% 4 3 4 4 6% 8% 37%	1581
May	1st to 10th	Night	18% 9% 3 5% 5% 3 6% 4 4 7% 35%	1440
	11th to 20th	Night	16% 8% 4 6% 5% 3 4 4 6% 8% 37%	1416
	21st to end	Night	19% 7% 4 6% 4 4 4 6% 4 6% 36%	1502
June	1st to 10th	Night	17% 5% 3 6% 6% 3 5% 5% 5% 6% 39%	1260
	11th to 20th	Night	15% 7% 3 8% 5% 3 4 4 5% 7% 38%	1260
	21st to end	Night	18% 6% 3 4 5% 4 4 5% 6% 8% 35%	1260
July	1st to 10th	Night	10% 5% 3 7% 5% 3 4 4 6% 7% 45%	1360
	11th to 20th	Night	11% 6% 2 5% 5% 4 5% 6% 6% 7% 42%	1440
	21st to end	Night	8% 5% 3 5% 4 3 7% 6% 7% 9% 44%	1575
August	1st to 10th	Night	10% 6% 2 6% 5% 4 5% 6% 7% 8% 42%	1432
	11th to 20th	Night	14% 5% 2 4 4 3 4 4 5% 8% 46%	1458
	21st to end	Night	15% 7% 3 4 4 3 3 5% 4 8% 45%	1940
September	1st to 10th	Night	15% 6% 3 5% 4 3 5% 4 6% 7% 45%	1800
	11th to 20th	Night	16% 8% 3 5% 4 4 4 5% 5% 7% 40%	1862
	21st to end	Night	20% 8% 4 7% 5% 2 4 5% 5% 7% 33%	1980
October	1st to 10th	Night	18% 11% 3 6% 6% 3 5% 5% 5% 6% 33%	2105
	11th to 20th	Night	19% 9% 3 5% 7% 4 5% 5% 6% 8% 28%	2265
	21st to end	Night	20% 13% 4 8% 7% 4 5% 5% 5% 5% 24%	2574
November	1st to 10th	Night	18% 12% 5% 7% 7% 4 5% 4 6% 7% 24%	2406
	11th to 20th	Night	19% 15% 6% 11% 8% 4 4 4 5% 5% 19%	2655
	21st to end	Night	17% 15% 6% 11% 8% 4 6% 4 5% 6% 18%	2812
December	1st to 10th	Night	11% 14% 6% 11% 9% 4 6% 5% 6% 7% 23%	2850
	11th to 20th	Night	12% 12% 6% 10% 7% 4 5% 5% 6% 7% 25%	3526
	21st to end	Night	25% 18% 5% 8% 7% 3 4 4 4 5% 18%	5195

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	42% 31% 14% 11% 2	2528
	11th to 20th	Day	45% 29% 11% 15% 1	2530
	21st to end	Day	53% 26% 10% 7% 4	2783
February	1st to 10th	Day	34% 37% 6% 14% 8% 1	1494
	11th to 20th	Day	30% 38% 11% 13% 7% 1	1628
	21st to end	Day	32% 38% 10% 12% 7% 1	1480
March	1st to 10th	Day	33% 38% 8% 13% 8% 1	1800
	11th to 20th	Day	34% 38% 8% 12% 8% 1	1851
	21st to end	Day	33% 38% 8% 12% 7% 1	2376
April	1st to 10th	Day	34% 39% 6% 15% 5% 1	2160
	11th to 20th	Day	37% 37% 8% 13% 6%	2181
	21st to end	Day	34% 38% 5% 10% 11% 2	2376
May	1st to 10th	Day	35% 39% 7% 14% 5%	2520
	11th to 20th	Day	28% 39% 8% 17% 7% 1	2483
	21st to end	Day	30% 40% 7% 12% 10% 1	2772
June	1st to 10th	Day	28% 39% 9% 15% 8%	2700
	11th to 20th	Day	27% 39% 9% 17% 7% 1	2700
	21st to end	Day	29% 38% 10% 17% 5%	2700
July	1st to 10th	Day	23% 39% 9% 19% 9%	2526
	11th to 20th	Day	24% 41% 9% 19% 6%	2445
	21st to end	Day	29% 41% 9% 16% 5% 1	2591
August	1st to 10th	Day	24% 41% 12% 17% 6% 1	2492
	11th to 20th	Day	23% 38% 8% 22% 9%	2443
	21st to end	Day	26% 39% 9% 19% 7% 1	2412
September	1st to 10th	Day	27% 39% 9% 19% 6%	2160
	11th to 20th	Day	30% 39% 12% 16% 3	2080
	21st to end	Day	34% 38% 12% 12% 4	1980
October	1st to 10th	Day	36% 39% 10% 14% 2	1854
	11th to 20th	Day	44% 37% 8% 10% 1	1694
	21st to end	Day	41% 39% 7% 10% 2	1782
November	1st to 10th	Day	38% 42% 8% 10% 2 1	1672
	11th to 20th	Day	42% 42% 8% 7% 2	1522
	21st to end	Day	42% 42% 8% 4 3	1365
December	1st to 10th	Day	40% 43% 10% 5% 2	1330
	11th to 20th	Day	40% 35% 14% 10% 1	1671
	21st to end	Day	54% 27% 6% 10% 2	2467
January	1st to 10th	Night	43% 31% 14% 11% 1	4428
	11th to 20th	Night	52% 28% 8% 11% 1	4440
	21st to end	Night	51% 27% 10% 8% 4	4884
February	1st to 10th	Night	35% 37% 8% 13% 7% 1	2561
	11th to 20th	Night	33% 38% 8% 11% 8%	2229
	21st to end	Night	35% 37% 7% 14% 5% 1	1776
March	1st to 10th	Night	33% 36% 10% 14% 7% 1	2160
	11th to 20th	Night	34% 37% 8% 13% 8%	2122
	21st to end	Night	33% 37% 9% 12% 7% 2	1980
April	1st to 10th	Night	37% 36% 6% 15% 7%	1800
	11th to 20th	Night	35% 37% 6% 14% 7%	1728
	21st to end	Night	33% 36% 7% 11% 10% 3	1581
May	1st to 10th	Night	35% 37% 7% 14% 6%	1440
	11th to 20th	Night	30% 38% 7% 16% 8% 1	1417
	21st to end	Night	32% 39% 6% 12% 10% 1	1503
June	1st to 10th	Night	31% 37% 7% 16% 8% 1	1260
	11th to 20th	Night	30% 37% 7% 16% 8% 1	1260
	21st to end	Night	32% 39% 11% 13% 5% 1	1260
July	1st to 10th	Night	25% 38% 9% 18% 9% 1	1320
	11th to 20th	Night	26% 40% 10% 18% 7%	1392
	21st to end	Night	24% 42% 10% 17% 5% 1	1487
August	1st to 10th	Night	26% 39% 14% 16% 4 1	1423
	11th to 20th	Night	23% 37% 8% 24% 8%	1458
	21st to end	Night	24% 37% 10% 22% 6%	1940
September	1st to 10th	Night	25% 38% 9% 19% 8%	1800
	11th to 20th	Night	27% 38% 13% 19% 3	1862
	21st to end	Night	34% 38% 9% 16% 3	1980
October	1st to 10th	Night	36% 38% 11% 12% 3	2105
	11th to 20th	Night	37% 39% 10% 12% 2	2265
	21st to end	Night	39% 38% 10% 10% 3	2574
November	1st to 10th	Night	36% 43% 7% 11% 2 1	2406
	11th to 20th	Night	44% 40% 8% 6% 1	2655
	21st to end	Night	40% 42% 10% 6% 3	2812
December	1st to 10th	Night	37% 43% 10% 7% 2	2850
	11th to 20th	Night	41% 34% 10% 11% 3	3525
	21st to end	Night	56% 26% 7% 10% 1	5195

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	18% 13% 44% 20% 6%	270
	11th to 20th	Day	11% 14% 41% 24% 8% 1	270
	21st to end	Day	15% 15% 44% 18% 7% 1	297
February	1st to 10th	Day	12% 17% 46% 18% 5% 1	252
	11th to 20th	Day	11% 26% 41% 17% 5%	240
	21st to end	Day	14% 30% 40% 13% 4	198
March	1st to 10th	Day	14% 25% 34% 22% 5%	240
	11th to 20th	Day	19% 23% 35% 18% 4 2	255
	21st to end	Day	17% 15% 38% 20% 7% 3	462
April	1st to 10th	Day	20% 21% 30% 22% 7% 1	420
	11th to 20th	Day	26% 20% 24% 19% 10% 1	412
	21st to end	Day	21% 18% 31% 19% 9% 3	456
May	1st to 10th	Day	19% 20% 35% 18% 6% 1	603
	11th to 20th	Day	18% 17% 36% 20% 6% 3	625
	21st to end	Day	20% 19% 35% 21% 5% 1	679
June	1st to 10th	Day	20% 13% 41% 19% 6% 2	630
	11th to 20th	Day	15% 19% 36% 22% 7% 1	630
	21st to end	Day	18% 11% 38% 22% 9% 2	630
July	1st to 10th	Day	11% 10% 40% 27% 10% 3	621
	11th to 20th	Day	11% 14% 42% 22% 8% 2	618
	21st to end	Day	12% 11% 35% 26% 11% 4	684
August	1st to 10th	Day	11% 14% 36% 26% 9% 3	626
	11th to 20th	Day	16% 11% 30% 27% 12% 4	579
	21st to end	Day	21% 12% 29% 23% 11% 3	495
September	1st to 10th	Day	16% 13% 31% 24% 12% 3	450
	11th to 20th	Day	23% 14% 29% 21% 11% 2	450
	21st to end	Day	22% 16% 28% 21% 11% 3	450
October	1st to 10th	Day	24% 21% 29% 17% 7% 2	324
	11th to 20th	Day	23% 22% 36% 17% 3	270
	21st to end	Day	29% 27% 30% 10% 3	297
November	1st to 10th	Day	21% 24% 34% 18% 3	270
	11th to 20th	Day	30% 22% 34% 10% 3	270
	21st to end	Day	23% 23% 33% 15% 5%	196
December	1st to 10th	Day	19% 16% 31% 24% 7% 2	180
	11th to 20th	Day	21% 22% 31% 18% 6% 1	180
	21st to end	Day	22% 18% 30% 22% 6% 1	209
January	1st to 10th	Night	17% 13% 38% 26% 6% 1	950
	11th to 20th	Night	16% 13% 34% 27% 8% 2	950
	21st to end	Night	16% 9% 35% 30% 10% 1	1045
February	1st to 10th	Night	14% 10% 37% 30% 9% 1	923
	11th to 20th	Night	15% 13% 34% 26% 11% 1	834
	21st to end	Night	12% 11% 40% 27% 9% 1	592
March	1st to 10th	Night	12% 11% 37% 28% 12% 1	720
	11th to 20th	Night	18% 15% 33% 27% 6% 1	698
	21st to end	Night	16% 9% 30% 29% 14% 2	594
April	1st to 10th	Night	19% 10% 31% 32% 6% 1	540
	11th to 20th	Night	22% 10% 28% 28% 12% 1	533
	21st to end	Night	21% 6% 28% 30% 13% 1	540
May	1st to 10th	Night	22% 7% 29% 31% 9% 1	540
	11th to 20th	Night	19% 9% 27% 34% 9% 1	531
	21st to end	Night	22% 9% 24% 35% 9% 1	535
June	1st to 10th	Night	15% 8% 33% 31% 11% 1	360
	11th to 20th	Night	16% 10% 29% 36% 8% 1	360
	21st to end	Night	20% 7% 29% 36% 7% 1	360
July	1st to 10th	Night	13% 5% 31% 38% 12% 1	445
	11th to 20th	Night	13% 6% 28% 40% 12% 1	522
	21st to end	Night	9% 5% 24% 42% 18% 2	591
August	1st to 10th	Night	14% 4 26% 41% 15%	537
	11th to 20th	Night	15% 4 22% 35% 23% 2	534
	21st to end	Night	18% 7% 30% 30% 15% 1	594
September	1st to 10th	Night	16% 8% 23% 34% 16% 3	540
	11th to 20th	Night	20% 10% 30% 27% 11% 1	602
	21st to end	Night	24% 10% 27% 26% 12% 1	720
October	1st to 10th	Night	23% 14% 29% 24% 9% 1	720
	11th to 20th	Night	25% 13% 31% 22% 8% 1	720
	21st to end	Night	28% 11% 32% 22% 7%	792
November	1st to 10th	Night	23% 16% 32% 22% 6%	740
	11th to 20th	Night	28% 14% 30% 20% 6% 1	945
	21st to end	Night	25% 17% 28% 24% 5%	950
December	1st to 10th	Night	18% 14% 36% 23% 8% 1	950
	11th to 20th	Night	18% 13% 32% 27% 9% 1	950
	21st to end	Night	24% 12% 28% 27% 7% 1	1045

Page generated at 2024-02-02 05:20:32. Version ac07

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