Mount Carleton Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mount Carleton Provincial Park clear sky chart from 2005-11-06 to 2026-10-14.

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	18% 13% 4 10% 6% 5% 5% 4 5% 6% 25%	150017
	Night	16% 14% 5% 11% 7% 5% 5% 3 4 5% 25%	141896
Transparency	Day	59% 5% 11% 16% 7% 1	153483
	Night	61% 5% 10% 16% 8% 1	146520
Seeing	Day	30% 19% 29% 15% 6% 1	18825
	Night	26% 18% 28% 21% 6% 1	26525

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	10% 20% 10% 16% 7% 7% 7% 3 3 4 14%	4093
	11th to 20th	Day	10% 17% 9% 24% 15% 7% 3 2 3 2 8%	4383
	21st to end	Day	4 8% 6% 19% 9% 10% 6% 7% 5% 5% 21%	5217
February	1st to 10th	Day	11% 14% 5% 13% 11% 9% 6% 4 5% 4 19%	1890
	11th to 20th	Day	12% 18% 7% 16% 7% 6% 6% 3 4 4 16%	1843
	21st to end	Day	9% 16% 6% 13% 8% 8% 6% 3 4 5% 22%	1672
March	1st to 10th	Day	18% 19% 5% 12% 6% 5% 5% 4 4 5% 19%	4755
	11th to 20th	Day	14% 21% 5% 11% 7% 5% 5% 3 4 5% 19%	5090
	21st to end	Day	20% 18% 6% 13% 5% 3 4 2 3 4 21%	5587
April	1st to 10th	Day	18% 20% 5% 11% 4 4 3 3 3 5% 24%	2510
	11th to 20th	Day	19% 17% 4 8% 5% 4 4 2 3 5% 28%	2702
	21st to end	Day	21% 15% 5% 9% 4 3 3 3 4 5% 27%	2730
May	1st to 10th	Day	24% 16% 4 9% 5% 4 4 3 4 5% 23%	7639
	11th to 20th	Day	20% 12% 3 8% 5% 4 4 3 5% 6% 29%	8246
	21st to end	Day	20% 12% 4 9% 5% 5% 4 3 6% 6% 26%	9716
June	1st to 10th	Day	24% 10% 3 7% 4 5% 5% 4 5% 6% 27%	3150
	11th to 20th	Day	22% 9% 3 7% 5% 5% 5% 4 6% 7% 28%	3150
	21st to end	Day	25% 11% 4 8% 5% 5% 4 4 5% 6% 23%	3150
July	1st to 10th	Day	15% 8% 3 8% 5% 6% 6% 5% 7% 8% 28%	8880
	11th to 20th	Day	19% 8% 3 8% 5% 5% 5% 5% 7% 8% 28%	8880
	21st to end	Day	14% 7% 2 7% 5% 5% 5% 4 7% 9% 36%	9087
August	1st to 10th	Day	18% 7% 3 8% 5% 5% 5% 5% 7% 8% 30%	6015
	11th to 20th	Day	19% 10% 4 10% 7% 6% 6% 5% 6% 7% 22%	5953
	21st to end	Day	18% 8% 3 6% 4 5% 5% 4 6% 8% 33%	6594
September	1st to 10th	Day	21% 8% 3 7% 3 3 3 4 5% 6% 36%	2533
	11th to 20th	Day	20% 9% 3 6% 4 3 4 2 4 5% 40%	2310
	21st to end	Day	19% 10% 2 6% 4 4 4 3 6% 5% 35%	2310
October	1st to 10th	Day	17% 14% 2 8% 4 3 4 3 5% 5% 34%	2147
	11th to 20th	Day	23% 17% 3 7% 3 4 4 3 4 5% 27%	2030
	21st to end	Day	25% 19% 5% 7% 4 3 4 3 4 4 22%	2010
November	1st to 10th	Day	20% 22% 5% 8% 4 3 3 2 5% 4 23%	1744
	11th to 20th	Day	19% 19% 6% 14% 4 4 3 3 4 4 19%	1680
	21st to end	Day	16% 21% 6% 16% 6% 4 4 3 5% 4 16%	1680
December	1st to 10th	Day	15% 17% 7% 20% 10% 6% 4 2 3 3 14%	2400
	11th to 20th	Day	16% 18% 6% 14% 10% 5% 4 2 4 3 17%	2688
	21st to end	Day	13% 20% 5% 16% 9% 5% 3 2 2 4 21%	3553
January	1st to 10th	Night	9% 20% 9% 17% 9% 7% 7% 3 4 4 10%	8831
	11th to 20th	Night	10% 18% 8% 19% 13% 6% 4 3 3 3 13%	8498
	21st to end	Night	4 9% 7% 17% 8% 8% 7% 6% 6% 5% 23%	8962
February	1st to 10th	Night	10% 14% 5% 14% 8% 9% 7% 3 5% 5% 21%	2730
	11th to 20th	Night	13% 19% 6% 12% 8% 7% 7% 4 3 3 18%	2663
	21st to end	Night	10% 16% 5% 12% 9% 7% 5% 3 4 4 26%	2130
March	1st to 10th	Night	17% 16% 6% 11% 5% 5% 6% 3 3 4 23%	5304
	11th to 20th	Night	19% 20% 5% 9% 5% 4 4 3 5% 5% 20%	5089
	21st to end	Night	24% 16% 5% 9% 5% 4 3 2 3 5% 22%	5587
April	1st to 10th	Night	21% 17% 4 11% 6% 5% 3 2 3 3 26%	2105
	11th to 20th	Night	20% 14% 4 6% 4 4 4 3 5% 5% 33%	1868
	21st to end	Night	21% 12% 4 6% 4 4 3 3 6% 6% 30%	1890
May	1st to 10th	Night	25% 15% 3 7% 4 3 3 3 4 5% 27%	5259
	11th to 20th	Night	22% 10% 3 7% 5% 4 4 3 5% 6% 31%	4677
	21st to end	Night	19% 11% 3 8% 5% 4 4 3 4 5% 34%	4499
June	1st to 10th	Night	20% 9% 3 7% 5% 4 4 4 5% 7% 33%	1470
	11th to 20th	Night	20% 7% 3 7% 4 5% 4 4 6% 7% 33%	1470
	21st to end	Night	21% 11% 3 9% 5% 5% 5% 3 6% 6% 26%	1470
July	1st to 10th	Night	20% 10% 3 7% 5% 5% 5% 4 5% 6% 31%	4110
	11th to 20th	Night	21% 8% 3 7% 4 4 5% 4 6% 7% 33%	4110
	21st to end	Night	13% 7% 3 6% 5% 5% 6% 5% 6% 7% 39%	4923
August	1st to 10th	Night	18% 8% 3 7% 6% 6% 5% 4 6% 7% 31%	4135
	11th to 20th	Night	18% 10% 3 8% 5% 5% 5% 4 6% 7% 29%	4092
	21st to end	Night	17% 9% 2 6% 4 3 4 3 5% 6% 40%	4531
September	1st to 10th	Night	17% 7% 2 5% 4 4 5% 4 5% 6% 42%	2082
	11th to 20th	Night	18% 9% 3 5% 4 3 3 3 5% 6% 42%	2310
	21st to end	Night	19% 8% 2 7% 3 3 4 4 4 5% 41%	2310
October	1st to 10th	Night	19% 11% 3 5% 4 4 4 3 4 5% 37%	2473
	11th to 20th	Night	21% 15% 3 6% 4 3 4 3 5% 5% 31%	2437
	21st to end	Night	20% 19% 4 9% 4 3 3 3 4 6% 23%	2829
November	1st to 10th	Night	21% 18% 5% 7% 5% 3 4 3 4 5% 25%	2772
	11th to 20th	Night	19% 19% 6% 13% 4 4 3 2 4 4 20%	2940
	21st to end	Night	17% 19% 7% 17% 6% 4 4 2 3 4 17%	2940
December	1st to 10th	Night	12% 16% 7% 18% 13% 5% 4 3 4 4 13%	4992
	11th to 20th	Night	17% 21% 6% 13% 9% 6% 4 3 3 3 16%	5741
	21st to end	Night	15% 18% 6% 13% 9% 7% 3 2 3 4 19%	7667

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	74% 5% 8% 9% 4	4094
	11th to 20th	Day	83% 4 5% 6% 3	4412
	21st to end	Day	61% 6% 7% 15% 11%	5217
February	1st to 10th	Day	67% 6% 8% 11% 7% 2	1890
	11th to 20th	Day	70% 5% 6% 13% 5% 1	1851
	21st to end	Day	62% 6% 7% 16% 8% 1	1672
March	1st to 10th	Day	67% 5% 7% 9% 10% 1	4759
	11th to 20th	Day	67% 6% 9% 12% 5% 1	5090
	21st to end	Day	68% 3 4 13% 10% 1	5587
April	1st to 10th	Day	63% 4 8% 13% 9% 2	2510
	11th to 20th	Day	59% 5% 8% 18% 9% 2	2702
	21st to end	Day	60% 4 8% 15% 10% 3	2730
May	1st to 10th	Day	64% 5% 9% 14% 8%	7651
	11th to 20th	Day	55% 6% 14% 17% 7% 1	8250
	21st to end	Day	58% 5% 9% 16% 10% 1	9717
June	1st to 10th	Day	55% 7% 10% 17% 9% 1	3150
	11th to 20th	Day	55% 6% 11% 17% 9% 1	3150
	21st to end	Day	61% 6% 11% 15% 7%	3150
July	1st to 10th	Day	51% 6% 15% 19% 9%	8805
	11th to 20th	Day	51% 5% 17% 22% 4	8799
	21st to end	Day	45% 5% 19% 26% 5%	8886
August	1st to 10th	Day	51% 6% 19% 16% 7%	6002
	11th to 20th	Day	60% 6% 16% 16% 3	5992
	21st to end	Day	48% 5% 16% 21% 10%	6594
September	1st to 10th	Day	47% 6% 14% 24% 9%	2533
	11th to 20th	Day	47% 4 12% 26% 11%	2310
	21st to end	Day	48% 6% 10% 24% 11%	2310
October	1st to 10th	Day	53% 4 13% 24% 6%	3433
	11th to 20th	Day	59% 5% 10% 17% 8%	3270
	21st to end	Day	60% 4 10% 19% 7%	3222
November	1st to 10th	Day	64% 6% 9% 15% 5%	1744
	11th to 20th	Day	70% 5% 9% 10% 5% 1	1680
	21st to end	Day	71% 6% 11% 10% 1	1680
December	1st to 10th	Day	77% 4 7% 9% 2	2400
	11th to 20th	Day	71% 5% 7% 13% 4	2688
	21st to end	Day	69% 4 8% 9% 8% 3	3553
January	1st to 10th	Night	76% 6% 7% 9% 1	8831
	11th to 20th	Night	75% 5% 6% 9% 5%	8544
	21st to end	Night	59% 5% 7% 16% 13% 1	8962
February	1st to 10th	Night	64% 5% 9% 13% 8% 1	2730
	11th to 20th	Night	69% 6% 7% 12% 6% 1	2666
	21st to end	Night	60% 6% 8% 14% 11% 1	2130
March	1st to 10th	Night	66% 4 7% 13% 9% 1	5313
	11th to 20th	Night	66% 5% 10% 12% 7%	5090
	21st to end	Night	66% 3 6% 13% 11% 1	5587
April	1st to 10th	Night	65% 4 7% 12% 10% 2	2105
	11th to 20th	Night	53% 5% 9% 19% 14% 1	1868
	21st to end	Night	53% 5% 9% 18% 13% 2	1890
May	1st to 10th	Night	58% 6% 9% 14% 12% 1	5265
	11th to 20th	Night	54% 5% 10% 20% 10% 1	4678
	21st to end	Night	53% 5% 10% 17% 14%	4500
June	1st to 10th	Night	51% 6% 11% 20% 10% 1	1470
	11th to 20th	Night	49% 7% 14% 18% 11% 1	1470
	21st to end	Night	59% 7% 11% 14% 9% 1	1470
July	1st to 10th	Night	53% 5% 13% 20% 9%	4075
	11th to 20th	Night	51% 6% 16% 24% 3	4068
	21st to end	Night	44% 6% 19% 24% 7%	4810
August	1st to 10th	Night	52% 7% 16% 18% 7%	4123
	11th to 20th	Night	52% 7% 22% 16% 3	4119
	21st to end	Night	44% 6% 17% 22% 11% 1	4531
September	1st to 10th	Night	41% 7% 15% 28% 8% 1	2082
	11th to 20th	Night	43% 4 16% 26% 10% 1	2310
	21st to end	Night	43% 7% 11% 26% 13% 1	2310
October	1st to 10th	Night	52% 4 11% 24% 9% 1	3967
	11th to 20th	Night	54% 4 11% 25% 6%	3936
	21st to end	Night	56% 5% 15% 17% 6%	4567
November	1st to 10th	Night	62% 5% 12% 16% 5%	2772
	11th to 20th	Night	68% 5% 10% 12% 5% 1	2940
	21st to end	Night	73% 6% 11% 8% 2 1	2940
December	1st to 10th	Night	74% 5% 8% 12% 2	4992
	11th to 20th	Night	74% 4 6% 11% 5%	5742
	21st to end	Night	69% 5% 8% 11% 7% 1	7667

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	31% 23% 30% 12% 3	220
	11th to 20th	Day	35% 25% 23% 13% 3 1	220
	21st to end	Day	26% 24% 33% 11% 5% 2	270
February	1st to 10th	Day	23% 26% 28% 16% 5% 2	430
	11th to 20th	Day	27% 26% 30% 12% 4	426
	21st to end	Day	30% 26% 28% 12% 3 1	416
March	1st to 10th	Day	30% 24% 33% 10% 2 1	540
	11th to 20th	Day	33% 22% 27% 12% 5% 1	540
	21st to end	Day	33% 23% 26% 12% 4 2	594
April	1st to 10th	Day	37% 27% 25% 9% 2 1	540
	11th to 20th	Day	38% 19% 27% 11% 3 1	532
	21st to end	Day	32% 22% 26% 15% 4 2	540
May	1st to 10th	Day	40% 15% 28% 12% 3 1	543
	11th to 20th	Day	30% 18% 28% 16% 7% 1	765
	21st to end	Day	33% 18% 28% 16% 5%	845
June	1st to 10th	Day	31% 17% 28% 15% 7% 1	780
	11th to 20th	Day	31% 17% 25% 18% 9% 1	780
	21st to end	Day	32% 14% 30% 17% 6% 1	780
July	1st to 10th	Day	23% 17% 32% 19% 8% 1	770
	11th to 20th	Day	21% 16% 33% 22% 7% 1	768
	21st to end	Day	23% 14% 35% 22% 6% 1	692
August	1st to 10th	Day	20% 15% 37% 20% 8% 1	566
	11th to 20th	Day	22% 13% 30% 26% 8% 1	559
	21st to end	Day	23% 18% 29% 18% 10% 1	627
September	1st to 10th	Day	25% 18% 31% 17% 8% 2	570
	11th to 20th	Day	28% 14% 31% 18% 7% 2	570
	21st to end	Day	27% 18% 28% 15% 8% 4	570
October	1st to 10th	Day	27% 19% 27% 17% 7% 3	477
	11th to 20th	Day	38% 17% 22% 16% 7% 1	429
	21st to end	Day	40% 20% 24% 10% 5% 1	462
November	1st to 10th	Day	41% 17% 24% 13% 4	425
	11th to 20th	Day	34% 23% 26% 12% 4	430
	21st to end	Day	35% 24% 25% 12% 4 1	430
December	1st to 10th	Day	33% 24% 28% 11% 4 1	257
	11th to 20th	Day	36% 29% 26% 8% 1	220
	21st to end	Day	34% 25% 27% 10% 5%	242
January	1st to 10th	Night	25% 23% 35% 14% 4	950
	11th to 20th	Night	26% 25% 27% 17% 5%	889
	21st to end	Night	18% 23% 33% 21% 4	924
February	1st to 10th	Night	19% 29% 29% 16% 5% 1	840
	11th to 20th	Night	27% 24% 30% 15% 3	823
	21st to end	Night	20% 19% 40% 16% 4 1	692
March	1st to 10th	Night	25% 21% 34% 17% 4	840
	11th to 20th	Night	30% 20% 26% 17% 7% 1	840
	21st to end	Night	25% 20% 29% 21% 5% 1	924
April	1st to 10th	Night	34% 20% 25% 18% 3	745
	11th to 20th	Night	30% 17% 27% 19% 7%	624
	21st to end	Night	32% 13% 26% 22% 6% 1	630
May	1st to 10th	Night	31% 14% 24% 26% 5%	630
	11th to 20th	Night	30% 12% 30% 22% 6% 1	622
	21st to end	Night	21% 18% 32% 24% 5%	463
June	1st to 10th	Night	25% 7% 30% 30% 6% 1	420
	11th to 20th	Night	22% 11% 26% 30% 12%	420
	21st to end	Night	26% 11% 27% 28% 8%	420
July	1st to 10th	Night	20% 10% 34% 27% 10%	410
	11th to 20th	Night	17% 9% 30% 33% 11%	408
	21st to end	Night	20% 8% 27% 33% 12% 1	467
August	1st to 10th	Night	18% 8% 29% 32% 13% 1	628
	11th to 20th	Night	19% 7% 25% 35% 13%	622
	21st to end	Night	18% 10% 27% 31% 13% 1	693
September	1st to 10th	Night	21% 12% 29% 28% 9%	668
	11th to 20th	Night	23% 10% 29% 27% 10% 1	840
	21st to end	Night	23% 13% 26% 26% 12% 1	840
October	1st to 10th	Night	26% 13% 28% 23% 9% 1	840
	11th to 20th	Night	29% 15% 27% 19% 9% 1	813
	21st to end	Night	32% 22% 25% 17% 4 1	880
November	1st to 10th	Night	35% 18% 26% 18% 3	875
	11th to 20th	Night	31% 23% 24% 16% 5% 1	950
	21st to end	Night	29% 24% 27% 14% 4 1	950
December	1st to 10th	Night	27% 23% 30% 16% 4 1	950
	11th to 20th	Night	33% 24% 26% 14% 3	950
	21st to end	Night	29% 25% 25% 16% 4 1	1045

Page generated at 2026-10-11 06:06:31. Version ac07

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