Long Sault Conservation Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Long Sault Conservation Area clear sky chart from 2005-11-06 to 2024-12-06.

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% 10% 3 8% 5% 4 5% 4 6% 7% 34%	101768
	Night	15% 10% 3 8% 5% 5% 4 4 5% 6% 35%	97954
Transparency	Day	46% 7% 14% 21% 11% 1	105368
	Night	46% 7% 13% 21% 11% 1	102442
Seeing	Day	19% 12% 29% 24% 12% 4	14511
	Night	19% 10% 30% 28% 12% 1	23881

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	17% 16% 5% 8% 6% 3 3 3 4 6% 30%	2517
	11th to 20th	Day	11% 20% 7% 15% 7% 6% 4 3 4 4 19%	2653
	21st to end	Day	21% 20% 6% 11% 6% 4 4 3 4 4 19%	3124
February	1st to 10th	Day	14% 17% 5% 12% 7% 6% 4 4 4 5% 22%	1710
	11th to 20th	Day	12% 16% 7% 12% 6% 5% 4 3 4 6% 25%	1663
	21st to end	Day	18% 14% 5% 10% 6% 4 4 3 4 5% 27%	1460
March	1st to 10th	Day	19% 13% 4 9% 4 4 3 3 4 6% 31%	3422
	11th to 20th	Day	11% 16% 5% 9% 5% 5% 5% 3 5% 6% 29%	3480
	21st to end	Day	17% 9% 3 6% 4 4 4 4 6% 5% 39%	3815
April	1st to 10th	Day	18% 13% 4 8% 4 4 5% 3 5% 6% 29%	2275
	11th to 20th	Day	20% 10% 3 6% 3 4 4 3 5% 6% 35%	2288
	21st to end	Day	20% 10% 3 7% 5% 4 4 3 5% 5% 33%	2470
May	1st to 10th	Day	19% 8% 3 7% 5% 4 4 4 6% 7% 32%	4187
	11th to 20th	Day	16% 9% 3 8% 5% 4 4 3 6% 9% 32%	4398
	21st to end	Day	13% 6% 2 6% 4 3 4 3 5% 8% 46%	4837
June	1st to 10th	Day	17% 7% 3 6% 5% 4 5% 4 6% 7% 35%	2660
	11th to 20th	Day	13% 6% 2 7% 5% 4 5% 5% 6% 9% 39%	2660
	21st to end	Day	15% 6% 2 6% 4 5% 5% 4 6% 8% 37%	2660
July	1st to 10th	Day	10% 6% 2 6% 5% 5% 5% 5% 8% 11% 39%	4440
	11th to 20th	Day	11% 5% 2 6% 4 4 5% 5% 7% 9% 41%	4440
	21st to end	Day	7% 5% 2 7% 5% 6% 6% 5% 7% 9% 42%	4628
August	1st to 10th	Day	16% 8% 3 7% 4 5% 5% 4 6% 7% 37%	4104
	11th to 20th	Day	13% 6% 3 7% 4 4 5% 5% 7% 10% 36%	4044
	21st to end	Day	9% 6% 2 6% 4 5% 4 5% 7% 9% 42%	4313
September	1st to 10th	Day	14% 6% 2 6% 4 5% 5% 4 5% 8% 42%	2280
	11th to 20th	Day	11% 5% 2 5% 4 4 5% 4 6% 8% 46%	2218
	21st to end	Day	14% 7% 2 7% 4 4 5% 4 6% 7% 39%	2020
October	1st to 10th	Day	19% 8% 2 6% 5% 5% 5% 4 6% 7% 33%	1900
	11th to 20th	Day	20% 10% 4 9% 5% 4 5% 3 4 6% 31%	1900
	21st to end	Day	24% 12% 4 9% 4 5% 4 3 5% 5% 25%	2090
November	1st to 10th	Day	15% 11% 3 8% 4 4 6% 4 6% 6% 34%	1674
	11th to 20th	Day	15% 14% 4 9% 5% 4 5% 4 7% 7% 26%	1600
	21st to end	Day	18% 18% 4 9% 5% 5% 4 3 5% 6% 23%	1600
December	1st to 10th	Day	16% 17% 6% 12% 6% 5% 5% 4 5% 6% 18%	1560
	11th to 20th	Day	17% 15% 4 10% 4 4 4 3 5% 6% 26%	1906
	21st to end	Day	26% 18% 5% 11% 5% 5% 5% 3 4 4 15%	2772
January	1st to 10th	Night	17% 15% 5% 10% 7% 5% 4 3 5% 5% 24%	4429
	11th to 20th	Night	14% 14% 5% 13% 9% 6% 5% 4 5% 5% 21%	4303
	21st to end	Night	19% 14% 6% 10% 5% 5% 4 3 4 5% 24%	4532
February	1st to 10th	Night	13% 16% 4 11% 6% 6% 6% 3 5% 6% 24%	2470
	11th to 20th	Night	14% 12% 5% 11% 7% 4 5% 3 5% 5% 28%	2403
	21st to end	Night	15% 12% 5% 10% 5% 4 5% 4 5% 6% 29%	1994
March	1st to 10th	Night	16% 11% 3 9% 5% 5% 4 3 4 6% 33%	3415
	11th to 20th	Night	14% 10% 4 9% 5% 5% 5% 4 5% 6% 34%	3479
	21st to end	Night	16% 7% 3 5% 3 4 4 4 4 7% 43%	3817
April	1st to 10th	Night	19% 11% 3 7% 4 4 4 4 4 6% 33%	1903
	11th to 20th	Night	17% 9% 2 6% 4 5% 4 4 5% 6% 37%	1857
	21st to end	Night	16% 10% 3 8% 4 4 4 4 5% 6% 34%	1710
May	1st to 10th	Night	18% 8% 2 6% 4 4 4 4 5% 5% 39%	2751
	11th to 20th	Night	14% 8% 3 7% 4 4 4 4 6% 7% 38%	2495
	21st to end	Night	10% 5% 2 6% 4 4 3 3 6% 9% 48%	2738
June	1st to 10th	Night	12% 6% 2 7% 5% 5% 6% 5% 6% 8% 38%	1520
	11th to 20th	Night	10% 5% 2 6% 6% 4 4 5% 7% 8% 44%	1520
	21st to end	Night	11% 7% 3 7% 5% 4 4 4 7% 8% 42%	1520
July	1st to 10th	Night	7% 5% 2 5% 4 4 5% 5% 7% 9% 47%	2520
	11th to 20th	Night	11% 5% 2 5% 4 3 4 4 6% 9% 49%	2520
	21st to end	Night	8% 5% 2 4 3 3 4 4 7% 8% 52%	2921
August	1st to 10th	Night	9% 5% 2 6% 4 5% 4 3 5% 8% 48%	2825
	11th to 20th	Night	12% 5% 2 5% 3 3 4 3 5% 7% 50%	2785
	21st to end	Night	10% 5% 2 5% 4 4 4 3 6% 8% 49%	3311
September	1st to 10th	Night	11% 5% 2 6% 4 4 4 4 7% 7% 46%	1900
	11th to 20th	Night	11% 4 2 5% 4 3 3 3 5% 7% 54%	1958
	21st to end	Night	15% 7% 3 6% 4 3 3 3 4 6% 43%	2159
October	1st to 10th	Night	15% 6% 2 7% 5% 4 4 3 6% 7% 39%	2280
	11th to 20th	Night	20% 8% 3 7% 5% 5% 4 4 5% 7% 32%	2280
	21st to end	Night	20% 10% 4 7% 4 4 5% 4 5% 6% 30%	2508
November	1st to 10th	Night	18% 8% 3 6% 4 5% 4 4 5% 7% 35%	2622
	11th to 20th	Night	17% 11% 3 8% 6% 5% 5% 3 5% 7% 29%	2800
	21st to end	Night	19% 13% 3 9% 6% 5% 5% 5% 5% 7% 24%	2800
December	1st to 10th	Night	18% 15% 5% 10% 6% 5% 5% 3 5% 6% 22%	2737
	11th to 20th	Night	15% 18% 4 9% 6% 6% 4 4 5% 6% 23%	3288
	21st to end	Night	27% 17% 4 9% 5% 5% 5% 3 4 5% 15%	4884

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	54% 10% 16% 12% 7% 1	2518
	11th to 20th	Day	68% 7% 10% 10% 5%	2653
	21st to end	Day	68% 7% 10% 9% 5% 1	3124
February	1st to 10th	Day	64% 6% 10% 15% 4 1	1710
	11th to 20th	Day	59% 6% 9% 15% 9% 1	1672
	21st to end	Day	59% 6% 10% 17% 8% 1	1460
March	1st to 10th	Day	52% 6% 15% 17% 10%	3425
	11th to 20th	Day	51% 8% 14% 17% 9% 1	3480
	21st to end	Day	42% 8% 11% 20% 17% 2	3815
April	1st to 10th	Day	54% 5% 12% 17% 10% 2	2275
	11th to 20th	Day	49% 6% 9% 21% 15% 1	2288
	21st to end	Day	51% 6% 11% 17% 13% 2	2470
May	1st to 10th	Day	48% 8% 12% 18% 13% 2	4199
	11th to 20th	Day	47% 9% 14% 19% 9% 1	4402
	21st to end	Day	35% 7% 15% 25% 14% 3	4837
June	1st to 10th	Day	44% 8% 13% 20% 14% 1	2660
	11th to 20th	Day	39% 8% 14% 23% 15% 2	2660
	21st to end	Day	41% 8% 16% 22% 13% 1	2660
July	1st to 10th	Day	36% 7% 17% 24% 15% 1	4370
	11th to 20th	Day	34% 8% 16% 33% 9% 1	4365
	21st to end	Day	34% 11% 14% 25% 15% 1	4480
August	1st to 10th	Day	44% 7% 15% 22% 12% 1	4091
	11th to 20th	Day	39% 8% 16% 28% 9%	4083
	21st to end	Day	34% 7% 15% 34% 10% 1	4313
September	1st to 10th	Day	39% 8% 14% 29% 10% 1	2280
	11th to 20th	Day	33% 7% 15% 30% 14%	2218
	21st to end	Day	43% 8% 15% 24% 9%	2020
October	1st to 10th	Day	38% 7% 15% 26% 13% 1	3160
	11th to 20th	Day	40% 6% 18% 21% 14% 1	3140
	21st to end	Day	50% 7% 15% 21% 6%	3428
November	1st to 10th	Day	49% 8% 14% 19% 9% 1	1674
	11th to 20th	Day	54% 8% 15% 14% 9% 1	1600
	21st to end	Day	60% 7% 13% 16% 4	1600
December	1st to 10th	Day	63% 8% 14% 12% 3	1560
	11th to 20th	Day	57% 10% 13% 14% 7%	1906
	21st to end	Day	71% 9% 8% 9% 3	2772
January	1st to 10th	Night	60% 8% 15% 13% 4 1	4429
	11th to 20th	Night	62% 8% 14% 12% 4 1	4303
	21st to end	Night	61% 8% 13% 12% 5% 1	4532
February	1st to 10th	Night	60% 7% 11% 17% 4 1	2470
	11th to 20th	Night	55% 7% 12% 17% 9%	2405
	21st to end	Night	54% 5% 14% 19% 7% 1	1994
March	1st to 10th	Night	51% 6% 11% 22% 8% 1	3425
	11th to 20th	Night	47% 6% 16% 19% 10% 1	3480
	21st to end	Night	38% 7% 12% 21% 20% 2	3817
April	1st to 10th	Night	50% 6% 10% 19% 13% 1	1903
	11th to 20th	Night	46% 6% 11% 18% 17% 2	1857
	21st to end	Night	47% 6% 13% 17% 15% 2	1710
May	1st to 10th	Night	45% 8% 12% 17% 16% 3	2758
	11th to 20th	Night	42% 10% 14% 22% 10% 2	2496
	21st to end	Night	30% 8% 14% 24% 21% 2	2739
June	1st to 10th	Night	40% 9% 12% 22% 15% 2	1520
	11th to 20th	Night	34% 8% 12% 22% 21% 2	1520
	21st to end	Night	39% 7% 13% 24% 16% 1	1520
July	1st to 10th	Night	31% 8% 14% 26% 20% 2	2480
	11th to 20th	Night	32% 6% 13% 34% 15% 1	2472
	21st to end	Night	28% 9% 15% 31% 17% 1	2828
August	1st to 10th	Night	34% 6% 13% 28% 16% 2	2814
	11th to 20th	Night	33% 6% 16% 31% 12% 1	2812
	21st to end	Night	32% 7% 13% 33% 15% 1	3311
September	1st to 10th	Night	34% 8% 14% 28% 14% 1	1900
	11th to 20th	Night	30% 6% 12% 33% 18% 1	1958
	21st to end	Night	41% 6% 12% 28% 12%	2159
October	1st to 10th	Night	32% 6% 12% 27% 23% 1	3800
	11th to 20th	Night	41% 6% 14% 29% 10%	3779
	21st to end	Night	40% 8% 15% 28% 8% 1	4120
November	1st to 10th	Night	45% 8% 13% 22% 12% 1	2622
	11th to 20th	Night	52% 7% 14% 17% 9% 1	2800
	21st to end	Night	56% 9% 17% 14% 4	2800
December	1st to 10th	Night	61% 8% 14% 13% 4	2737
	11th to 20th	Night	59% 9% 13% 14% 4	3288
	21st to end	Night	69% 8% 11% 9% 3	4884

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	24% 19% 30% 18% 7% 1	180
	11th to 20th	Day	25% 25% 30% 14% 5% 1	219
	21st to end	Day	26% 18% 33% 20% 2	297
February	1st to 10th	Day	22% 30% 31% 14% 3	270
	11th to 20th	Day	23% 23% 41% 11% 2	270
	21st to end	Day	29% 25% 33% 12% 1	272
March	1st to 10th	Day	23% 16% 37% 19% 4	460
	11th to 20th	Day	22% 21% 32% 20% 4	460
	21st to end	Day	30% 12% 33% 18% 6% 1	506
April	1st to 10th	Day	23% 15% 35% 20% 6% 1	460
	11th to 20th	Day	29% 15% 26% 17% 9% 4	452
	21st to end	Day	25% 13% 35% 17% 9% 1	460
May	1st to 10th	Day	22% 10% 29% 24% 10% 5%	463
	11th to 20th	Day	19% 7% 30% 27% 14% 4	487
	21st to end	Day	14% 8% 25% 30% 17% 6%	529
June	1st to 10th	Day	17% 8% 32% 29% 13% 2	490
	11th to 20th	Day	14% 8% 27% 30% 18% 3	490
	21st to end	Day	20% 7% 28% 29% 13% 4	490
July	1st to 10th	Day	11% 4 22% 35% 23% 5%	485
	11th to 20th	Day	14% 5% 23% 30% 20% 8%	484
	21st to end	Day	8% 4 30% 36% 15% 6%	532
August	1st to 10th	Day	13% 4 23% 33% 19% 9%	486
	11th to 20th	Day	13% 3 22% 31% 22% 9%	479
	21st to end	Day	13% 6% 26% 28% 18% 9%	539
September	1st to 10th	Day	13% 7% 25% 26% 19% 10%	490
	11th to 20th	Day	11% 5% 21% 28% 19% 16%	490
	21st to end	Day	15% 10% 27% 28% 14% 6%	490
October	1st to 10th	Day	19% 12% 28% 22% 15% 4	490
	11th to 20th	Day	21% 16% 32% 22% 7% 2	490
	21st to end	Day	27% 17% 29% 21% 6%	539
November	1st to 10th	Day	22% 16% 29% 22% 9% 1	294
	11th to 20th	Day	23% 22% 36% 14% 5% 1	200
	21st to end	Day	28% 21% 34% 13% 4	200
December	1st to 10th	Day	21% 20% 37% 15% 7% 1	190
	11th to 20th	Day	24% 25% 30% 17% 3 1	180
	21st to end	Day	28% 20% 36% 15% 1	198
January	1st to 10th	Night	22% 16% 38% 18% 6%	760
	11th to 20th	Night	28% 13% 34% 21% 4 1	760
	21st to end	Night	19% 12% 35% 26% 6%	836
February	1st to 10th	Night	21% 16% 40% 22% 2	760
	11th to 20th	Night	20% 15% 39% 22% 4	743
	21st to end	Night	20% 15% 39% 21% 4	628
March	1st to 10th	Night	20% 14% 36% 26% 4 1	760
	11th to 20th	Night	21% 14% 34% 26% 4 1	760
	21st to end	Night	19% 11% 34% 26% 10%	836
April	1st to 10th	Night	23% 12% 33% 27% 5%	760
	11th to 20th	Night	19% 12% 33% 26% 10% 1	733
	21st to end	Night	21% 8% 32% 28% 11%	570
May	1st to 10th	Night	20% 5% 28% 31% 14% 3	527
	11th to 20th	Night	14% 7% 28% 36% 14%	374
	21st to end	Night	11% 5% 22% 40% 21% 1	411
June	1st to 10th	Night	13% 3 30% 39% 14% 1	380
	11th to 20th	Night	10% 5% 25% 41% 18% 1	380
	21st to end	Night	12% 5% 24% 40% 18% 1	380
July	1st to 10th	Night	6% 3 19% 48% 22% 1	370
	11th to 20th	Night	10% 4 19% 42% 24% 1	368
	21st to end	Night	10% 2 20% 44% 22% 2	523
August	1st to 10th	Night	10% 2 16% 39% 29% 3	567
	11th to 20th	Night	9% 2 16% 38% 29% 4	564
	21st to end	Night	11% 4 22% 36% 25% 2	736
September	1st to 10th	Night	13% 5% 21% 35% 22% 4	760
	11th to 20th	Night	12% 4 18% 33% 27% 7%	760
	21st to end	Night	19% 8% 19% 29% 21% 4	760
October	1st to 10th	Night	19% 5% 28% 27% 18% 2	760
	11th to 20th	Night	22% 12% 29% 27% 9% 1	760
	21st to end	Night	26% 9% 31% 28% 5%	836
November	1st to 10th	Night	22% 11% 26% 29% 11% 1	780
	11th to 20th	Night	21% 16% 31% 24% 7% 2	800
	21st to end	Night	25% 14% 33% 23% 6%	800
December	1st to 10th	Night	27% 15% 34% 20% 4	783
	11th to 20th	Night	23% 12% 38% 23% 4 1	760
	21st to end	Night	30% 13% 36% 19% 3	836

Page generated at 2024-12-03 06:45:13. Version ac07

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