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 2025-06-10.

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% 14% 4 10% 6% 5% 4 3 5% 5% 25%	119300
	Night	17% 15% 5% 11% 7% 5% 4 3 4 5% 25%	119054
Transparency	Day	60% 6% 11% 16% 7% 1	122809
	Night	61% 5% 10% 15% 8% 1	123707
Seeing	Day	30% 19% 29% 16% 6% 1	16956
	Night	26% 18% 28% 21% 7% 1	24862

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% 21% 10% 16% 8% 7% 4 2 2 3 14%	3157
	11th to 20th	Day	9% 15% 9% 24% 16% 7% 3 2 3 2 10%	3368
	21st to end	Day	5% 8% 5% 19% 7% 8% 8% 6% 6% 5% 23%	4025
February	1st to 10th	Day	11% 15% 5% 12% 10% 9% 6% 4 5% 4 18%	1800
	11th to 20th	Day	13% 18% 7% 15% 8% 6% 6% 3 4 4 16%	1753
	21st to end	Day	10% 16% 6% 12% 8% 8% 6% 3 4 5% 22%	1595
March	1st to 10th	Day	18% 19% 5% 12% 6% 4 5% 3 4 5% 19%	4651
	11th to 20th	Day	14% 21% 5% 11% 7% 5% 5% 3 4 5% 19%	4980
	21st to end	Day	21% 18% 6% 13% 5% 3 4 2 3 4 21%	5466
April	1st to 10th	Day	18% 20% 5% 11% 4 4 3 3 3 5% 23%	2391
	11th to 20th	Day	19% 17% 4 8% 4 4 4 2 3 5% 28%	2572
	21st to end	Day	22% 16% 5% 8% 4 3 3 3 4 5% 27%	2600
May	1st to 10th	Day	22% 17% 4 9% 5% 4 4 3 4 5% 24%	5886
	11th to 20th	Day	22% 13% 3 8% 4 4 4 3 5% 6% 28%	6344
	21st to end	Day	20% 11% 3 8% 5% 5% 4 3 6% 7% 27%	7451
June	1st to 10th	Day	25% 10% 3 7% 4 5% 4 4 5% 6% 27%	2985
	11th to 20th	Day	22% 9% 3 7% 5% 5% 4 4 6% 7% 29%	2850
	21st to end	Day	26% 11% 3 8% 5% 5% 4 4 4 6% 23%	2850
July	1st to 10th	Day	18% 9% 3 9% 5% 6% 5% 4 6% 7% 27%	4760
	11th to 20th	Day	18% 8% 3 7% 6% 5% 5% 5% 6% 8% 29%	4760
	21st to end	Day	16% 7% 2 6% 5% 5% 5% 4 7% 8% 35%	4868
August	1st to 10th	Day	18% 7% 3 8% 5% 6% 5% 5% 6% 7% 29%	4105
	11th to 20th	Day	17% 9% 4 9% 6% 6% 6% 5% 6% 8% 24%	4045
	21st to end	Day	20% 8% 2 6% 4 5% 4 4 5% 7% 35%	4532
September	1st to 10th	Day	22% 9% 3 7% 3 3 3 4 5% 6% 36%	2292
	11th to 20th	Day	21% 9% 2 6% 3 3 3 2 4 5% 41%	2090
	21st to end	Day	20% 11% 2 6% 4 3 4 3 6% 6% 35%	2090
October	1st to 10th	Day	17% 14% 3 8% 4 3 4 2 6% 6% 35%	1943
	11th to 20th	Day	23% 17% 3 7% 3 4 4 3 4 5% 27%	1900
	21st to end	Day	25% 19% 5% 7% 4 3 4 3 4 4 22%	1910
November	1st to 10th	Day	20% 21% 5% 8% 4 3 3 2 5% 4 23%	1659
	11th to 20th	Day	19% 19% 5% 14% 4 4 3 3 4 4 20%	1600
	21st to end	Day	16% 21% 5% 16% 6% 4 4 3 5% 4 17%	1600
December	1st to 10th	Day	16% 17% 7% 20% 11% 5% 4 2 3 3 13%	2328
	11th to 20th	Day	16% 18% 7% 13% 9% 5% 4 2 4 3 18%	2618
	21st to end	Day	13% 20% 5% 16% 9% 5% 3 2 3 4 21%	3476
January	1st to 10th	Night	9% 23% 10% 18% 10% 8% 4 2 4 3 9%	6808
	11th to 20th	Night	10% 17% 7% 19% 14% 5% 4 3 3 3 14%	6522
	21st to end	Night	5% 10% 6% 15% 6% 6% 7% 4 5% 6% 29%	6929
February	1st to 10th	Night	10% 15% 5% 13% 8% 9% 7% 3 5% 5% 21%	2600
	11th to 20th	Night	13% 19% 6% 12% 8% 7% 7% 4 4 3 17%	2533
	21st to end	Night	10% 17% 5% 11% 9% 7% 5% 3 4 4 25%	2032
March	1st to 10th	Night	18% 16% 6% 11% 5% 5% 6% 3 3 4 23%	5188
	11th to 20th	Night	19% 20% 5% 9% 5% 4 4 3 5% 5% 21%	4979
	21st to end	Night	25% 16% 5% 9% 5% 4 3 2 3 5% 22%	5466
April	1st to 10th	Night	21% 17% 4 11% 6% 5% 3 2 3 3 26%	2005
	11th to 20th	Night	20% 14% 4 6% 4 4 4 3 5% 5% 34%	1778
	21st to end	Night	22% 12% 4 6% 4 4 3 3 5% 6% 30%	1800
May	1st to 10th	Night	22% 14% 3 7% 5% 3 3 3 5% 5% 29%	4054
	11th to 20th	Night	24% 11% 3 7% 5% 4 4 3 5% 5% 31%	3603
	21st to end	Night	19% 9% 2 6% 5% 4 5% 3 5% 6% 36%	3454
June	1st to 10th	Night	20% 10% 3 7% 5% 4 4 4 5% 7% 32%	1399
	11th to 20th	Night	18% 7% 3 7% 4 5% 5% 4 6% 7% 34%	1330
	21st to end	Night	22% 11% 3 9% 5% 4 5% 3 6% 6% 26%	1330
July	1st to 10th	Night	16% 11% 3 7% 5% 5% 5% 4 5% 7% 32%	2210
	11th to 20th	Night	22% 9% 3 7% 4 4 4 3 6% 6% 31%	2210
	21st to end	Night	17% 8% 3 6% 4 4 4 4 5% 6% 39%	2652
August	1st to 10th	Night	19% 8% 3 7% 6% 5% 5% 5% 6% 7% 28%	2825
	11th to 20th	Night	16% 7% 3 8% 5% 5% 6% 4 7% 8% 30%	2782
	21st to end	Night	17% 9% 2 6% 4 3 3 3 5% 7% 42%	3124
September	1st to 10th	Night	18% 6% 2 5% 4 3 5% 4 5% 6% 42%	1883
	11th to 20th	Night	19% 9% 3 5% 3 3 3 3 5% 6% 42%	2090
	21st to end	Night	19% 8% 2 6% 4 3 4 3 5% 6% 40%	2090
October	1st to 10th	Night	20% 10% 3 6% 4 4 4 3 5% 5% 37%	2237
	11th to 20th	Night	22% 15% 3 6% 4 3 4 3 5% 5% 30%	2280
	21st to end	Night	21% 19% 4 8% 4 3 3 3 4 6% 24%	2687
November	1st to 10th	Night	21% 17% 5% 8% 5% 4 4 3 4 5% 26%	2637
	11th to 20th	Night	19% 19% 6% 13% 4 4 3 2 4 5% 21%	2800
	21st to end	Night	17% 19% 7% 16% 6% 4 4 2 3 4 17%	2800
December	1st to 10th	Night	12% 16% 7% 18% 13% 5% 4 3 4 4 13%	4844
	11th to 20th	Night	18% 21% 6% 13% 9% 6% 4 3 3 3 16%	5591
	21st to end	Night	15% 18% 6% 13% 9% 7% 3 2 3 4 19%	7502

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	76% 6% 9% 7% 3	3158
	11th to 20th	Day	81% 4 6% 6% 3	3397
	21st to end	Day	58% 6% 6% 15% 13% 1	4025
February	1st to 10th	Day	67% 6% 8% 11% 7% 2	1800
	11th to 20th	Day	70% 6% 7% 12% 5% 1	1761
	21st to end	Day	63% 6% 7% 17% 7% 1	1595
March	1st to 10th	Day	67% 5% 7% 9% 11% 1	4655
	11th to 20th	Day	66% 7% 9% 12% 5% 1	4980
	21st to end	Day	68% 3 4 14% 10% 1	5466
April	1st to 10th	Day	64% 4 8% 13% 9% 2	2391
	11th to 20th	Day	58% 5% 8% 18% 9% 2	2572
	21st to end	Day	60% 4 8% 15% 9% 3	2600
May	1st to 10th	Day	63% 5% 8% 15% 8% 1	5897
	11th to 20th	Day	56% 7% 15% 15% 6% 1	6348
	21st to end	Day	54% 6% 11% 20% 8%	7451
June	1st to 10th	Day	56% 8% 10% 16% 9% 1	2985
	11th to 20th	Day	54% 6% 12% 18% 9% 1	2850
	21st to end	Day	61% 7% 11% 15% 6%	2850
July	1st to 10th	Day	54% 6% 15% 16% 9%	4685
	11th to 20th	Day	51% 6% 18% 21% 4	4679
	21st to end	Day	45% 7% 18% 21% 8%	4712
August	1st to 10th	Day	52% 7% 17% 17% 7%	4092
	11th to 20th	Day	55% 7% 17% 17% 3	4084
	21st to end	Day	48% 5% 16% 18% 12%	4532
September	1st to 10th	Day	48% 6% 14% 23% 9%	2292
	11th to 20th	Day	47% 4 12% 26% 11%	2090
	21st to end	Day	49% 6% 11% 25% 10%	2090
October	1st to 10th	Day	53% 3 13% 24% 7%	3229
	11th to 20th	Day	59% 5% 10% 18% 8%	3140
	21st to end	Day	59% 4 10% 19% 8%	3122
November	1st to 10th	Day	64% 6% 9% 16% 5%	1659
	11th to 20th	Day	69% 5% 9% 11% 5% 1	1600
	21st to end	Day	70% 6% 12% 11% 1	1600
December	1st to 10th	Day	78% 4 7% 8% 2	2328
	11th to 20th	Day	71% 5% 7% 13% 4	2618
	21st to end	Day	69% 4 8% 9% 8% 3	3476
January	1st to 10th	Night	79% 6% 7% 7% 1	6808
	11th to 20th	Night	75% 4 7% 9% 5%	6568
	21st to end	Night	54% 5% 8% 18% 14% 1	6929
February	1st to 10th	Night	64% 5% 9% 13% 8% 1	2600
	11th to 20th	Night	70% 7% 7% 11% 6% 1	2536
	21st to end	Night	61% 6% 8% 14% 9% 1	2032
March	1st to 10th	Night	66% 4 6% 13% 9% 1	5197
	11th to 20th	Night	66% 5% 10% 12% 8%	4980
	21st to end	Night	66% 3 6% 13% 11% 1	5466
April	1st to 10th	Night	64% 4 6% 12% 10% 2	2005
	11th to 20th	Night	52% 5% 9% 19% 14% 1	1778
	21st to end	Night	54% 6% 9% 18% 12% 2	1800
May	1st to 10th	Night	55% 7% 10% 13% 14% 1	4060
	11th to 20th	Night	55% 5% 11% 19% 8% 1	3604
	21st to end	Night	49% 6% 13% 21% 11%	3455
June	1st to 10th	Night	52% 6% 11% 20% 10% 1	1399
	11th to 20th	Night	47% 7% 15% 18% 11% 2	1330
	21st to end	Night	58% 7% 11% 14% 9% 1	1330
July	1st to 10th	Night	50% 7% 14% 21% 8%	2175
	11th to 20th	Night	53% 6% 17% 19% 5% 1	2168
	21st to end	Night	44% 8% 18% 21% 9%	2568
August	1st to 10th	Night	53% 8% 15% 19% 5%	2813
	11th to 20th	Night	48% 9% 21% 17% 4	2809
	21st to end	Night	42% 6% 15% 22% 13% 1	3124
September	1st to 10th	Night	41% 8% 15% 27% 9% 1	1883
	11th to 20th	Night	43% 4 16% 25% 11%	2090
	21st to end	Night	43% 7% 11% 25% 12% 1	2090
October	1st to 10th	Night	52% 4 11% 23% 9% 1	3731
	11th to 20th	Night	54% 4 11% 25% 6%	3779
	21st to end	Night	55% 5% 16% 18% 6%	4425
November	1st to 10th	Night	61% 5% 13% 16% 5%	2637
	11th to 20th	Night	67% 4 10% 12% 5% 1	2800
	21st to end	Night	72% 5% 11% 8% 2 1	2800
December	1st to 10th	Night	74% 5% 8% 12% 2	4844
	11th to 20th	Night	74% 4 6% 11% 5%	5592
	21st to end	Night	69% 5% 8% 11% 7% 1	7502

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	32% 22% 32% 11% 3 1	200
	11th to 20th	Day	33% 25% 24% 14% 3 2	200
	21st to end	Day	26% 23% 33% 11% 5% 2	246
February	1st to 10th	Day	25% 26% 29% 15% 5% 1	400
	11th to 20th	Day	28% 27% 30% 12% 3	396
	21st to end	Day	30% 25% 29% 12% 3 1	387
March	1st to 10th	Day	29% 23% 35% 11% 2 1	500
	11th to 20th	Day	30% 23% 29% 13% 5% 1	500
	21st to end	Day	32% 24% 26% 12% 4 2	550
April	1st to 10th	Day	36% 27% 25% 9% 2 1	500
	11th to 20th	Day	37% 19% 28% 12% 4 1	492
	21st to end	Day	35% 22% 25% 14% 3 2	500
May	1st to 10th	Day	39% 15% 28% 13% 3 1	503
	11th to 20th	Day	29% 17% 28% 17% 8% 1	715
	21st to end	Day	33% 18% 28% 16% 5% 1	790
June	1st to 10th	Day	32% 17% 28% 15% 7% 1	725
	11th to 20th	Day	28% 18% 25% 19% 9% 1	680
	21st to end	Day	32% 14% 31% 17% 6% 1	680
July	1st to 10th	Day	22% 17% 32% 19% 8% 1	670
	11th to 20th	Day	19% 15% 33% 23% 8% 1	668
	21st to end	Day	22% 13% 35% 23% 6% 1	598
August	1st to 10th	Day	21% 16% 36% 19% 7% 1	486
	11th to 20th	Day	23% 14% 29% 27% 8%	479
	21st to end	Day	24% 16% 29% 19% 12% 1	539
September	1st to 10th	Day	25% 18% 30% 18% 8% 1	490
	11th to 20th	Day	26% 14% 32% 18% 7% 2	490
	21st to end	Day	27% 19% 28% 14% 8% 4	490
October	1st to 10th	Day	26% 19% 26% 18% 8% 3	413
	11th to 20th	Day	37% 17% 22% 16% 7% 1	390
	21st to end	Day	41% 20% 24% 10% 5%	429
November	1st to 10th	Day	39% 18% 24% 14% 5%	395
	11th to 20th	Day	34% 24% 25% 13% 4 1	400
	21st to end	Day	34% 25% 25% 12% 4 1	400
December	1st to 10th	Day	32% 23% 29% 11% 5% 1	235
	11th to 20th	Day	37% 27% 27% 9% 2	200
	21st to end	Day	34% 26% 26% 10% 5%	220
January	1st to 10th	Night	24% 23% 34% 14% 4	900
	11th to 20th	Night	26% 24% 27% 17% 5%	845
	21st to end	Night	18% 23% 33% 21% 5%	880
February	1st to 10th	Night	20% 30% 29% 16% 5% 1	800
	11th to 20th	Night	28% 24% 31% 13% 3	783
	21st to end	Night	20% 19% 39% 17% 4 1	660
March	1st to 10th	Night	23% 20% 35% 18% 4	800
	11th to 20th	Night	28% 20% 27% 17% 7% 1	800
	21st to end	Night	24% 19% 29% 21% 6% 1	880
April	1st to 10th	Night	33% 20% 25% 19% 3	710
	11th to 20th	Night	28% 17% 28% 19% 7%	594
	21st to end	Night	34% 14% 25% 21% 6% 1	600
May	1st to 10th	Night	30% 14% 24% 27% 5% 1	600
	11th to 20th	Night	30% 11% 30% 23% 6% 1	592
	21st to end	Night	21% 17% 32% 24% 5%	441
June	1st to 10th	Night	25% 7% 29% 31% 7% 1	400
	11th to 20th	Night	19% 11% 27% 31% 12%	380
	21st to end	Night	27% 11% 27% 28% 8%	380
July	1st to 10th	Night	19% 9% 34% 28% 10%	370
	11th to 20th	Night	16% 9% 30% 34% 12% 1	368
	21st to end	Night	21% 7% 25% 33% 13% 1	422
August	1st to 10th	Night	18% 8% 30% 31% 12% 1	568
	11th to 20th	Night	20% 8% 25% 35% 13% 1	562
	21st to end	Night	17% 9% 27% 31% 14% 1	627
September	1st to 10th	Night	21% 13% 30% 27% 9%	604
	11th to 20th	Night	23% 9% 29% 27% 10% 1	760
	21st to end	Night	23% 13% 27% 26% 11%	760
October	1st to 10th	Night	26% 13% 27% 24% 9% 1	760
	11th to 20th	Night	29% 15% 27% 19% 8% 1	760
	21st to end	Night	33% 22% 25% 17% 4 1	836
November	1st to 10th	Night	33% 18% 26% 19% 4	830
	11th to 20th	Night	32% 22% 24% 16% 5% 1	900
	21st to end	Night	29% 24% 28% 14% 4	900
December	1st to 10th	Night	27% 22% 30% 16% 4 1	900
	11th to 20th	Night	32% 24% 25% 14% 3	900
	21st to end	Night	30% 24% 24% 16% 4 1	990

Page generated at 2025-06-07 11:28:13. Version ac07

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