Jasper Maligne Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Jasper Maligne Lake clear sky chart from 2005-11-06 to 2024-11-01.

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	10% 16% 6% 13% 7% 6% 5% 4 5% 6% 23%	102025
	Night	7% 15% 6% 13% 8% 6% 5% 4 6% 7% 23%	96988
Transparency	Day	62% 6% 11% 14% 6% 1	101769
	Night	60% 8% 12% 14% 6% 1	96891
Seeing	Day	23% 19% 29% 20% 8% 2	16057
	Night	14% 17% 36% 23% 9% 1	24325

By Month

Percentage Cloud Cover NW (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	2 12% 8% 23% 9% 11% 6% 5% 7% 6% 11%	1899
	11th to 20th	Day	4 15% 7% 16% 8% 5% 3 5% 5% 5% 26%	2258
	21st to end	Day	5% 26% 9% 13% 8% 5% 5% 4 5% 6% 14%	2794
February	1st to 10th	Day	4 15% 11% 17% 7% 5% 7% 3 6% 6% 18%	1520
	11th to 20th	Day	2 15% 7% 22% 9% 6% 6% 5% 6% 5% 17%	1552
	21st to end	Day	2 11% 8% 20% 11% 9% 5% 4 6% 6% 18%	1570
March	1st to 10th	Day	1 13% 8% 17% 10% 8% 7% 5% 7% 6% 18%	3138
	11th to 20th	Day	2 15% 11% 14% 6% 6% 5% 3 5% 6% 27%	3242
	21st to end	Day	2 19% 9% 21% 8% 5% 5% 3 5% 5% 18%	4158
April	1st to 10th	Day	5% 22% 12% 18% 9% 7% 5% 4 4 3 11%	2280
	11th to 20th	Day	4 21% 8% 17% 8% 6% 5% 3 5% 5% 17%	2389
	21st to end	Day	8% 25% 7% 13% 7% 5% 3 4 5% 5% 17%	2593
May	1st to 10th	Day	9% 24% 6% 12% 5% 4 4 3 5% 6% 21%	4420
	11th to 20th	Day	12% 20% 5% 12% 6% 5% 5% 4 6% 7% 19%	4598
	21st to end	Day	14% 29% 5% 13% 7% 4 4 3 4 4 13%	5161
June	1st to 10th	Day	19% 15% 4 11% 7% 6% 5% 4 5% 6% 17%	3011
	11th to 20th	Day	22% 19% 5% 13% 7% 6% 5% 4 5% 4 12%	3040
	21st to end	Day	17% 13% 6% 12% 7% 5% 5% 3 5% 6% 20%	3040
July	1st to 10th	Day	15% 11% 3 8% 5% 5% 4 3 4 5% 35%	5060
	11th to 20th	Day	12% 7% 3 8% 6% 5% 5% 4 5% 6% 39%	4974
	21st to end	Day	17% 11% 4 9% 6% 5% 5% 4 5% 6% 29%	4853
August	1st to 10th	Day	15% 8% 3 9% 6% 6% 6% 4 5% 6% 32%	4401
	11th to 20th	Day	14% 9% 4 11% 7% 7% 6% 4 6% 6% 27%	4330
	21st to end	Day	18% 14% 4 9% 5% 5% 5% 3 5% 5% 28%	4464
September	1st to 10th	Day	17% 12% 4 9% 5% 4 4 4 5% 4 31%	2280
	11th to 20th	Day	13% 15% 4 8% 5% 5% 4 3 5% 6% 31%	2204
	21st to end	Day	15% 19% 3 10% 5% 4 4 4 5% 6% 26%	2090
October	1st to 10th	Day	11% 21% 5% 9% 6% 5% 4 4 6% 5% 25%	1952
	11th to 20th	Day	9% 21% 5% 11% 5% 5% 6% 3 5% 7% 22%	1738
	21st to end	Day	6% 19% 8% 13% 7% 7% 5% 4 5% 6% 21%	1881
November	1st to 10th	Day	6% 19% 7% 14% 10% 7% 7% 4 6% 5% 16%	1556
	11th to 20th	Day	3 15% 8% 14% 7% 5% 6% 6% 7% 7% 23%	1330
	21st to end	Day	3 18% 7% 13% 8% 8% 4 5% 7% 8% 19%	1330
December	1st to 10th	Day	4 14% 7% 19% 10% 7% 5% 4 4 4 22%	1330
	11th to 20th	Day	4 16% 7% 16% 9% 8% 7% 5% 5% 7% 17%	1499
	21st to end	Day	1 20% 7% 12% 7% 5% 5% 4 6% 8% 25%	2090
January	1st to 10th	Night	2 15% 9% 24% 13% 7% 6% 4 5% 5% 11%	5046
	11th to 20th	Night	3 13% 6% 14% 8% 6% 6% 5% 6% 8% 25%	4670
	21st to end	Night	6% 25% 10% 15% 8% 7% 5% 3 4 4 14%	4862
February	1st to 10th	Night	4 19% 8% 17% 9% 5% 7% 4 5% 5% 17%	2660
	11th to 20th	Night	3 16% 7% 19% 9% 6% 6% 5% 5% 6% 19%	2509
	21st to end	Night	2 13% 7% 14% 11% 8% 6% 5% 7% 7% 21%	1884
March	1st to 10th	Night	1 10% 7% 18% 13% 9% 8% 5% 7% 6% 15%	3736
	11th to 20th	Night	3 16% 11% 12% 7% 4 5% 4 9% 7% 23%	3737
	21st to end	Night	2 17% 10% 17% 7% 6% 5% 4 6% 6% 21%	3493
April	1st to 10th	Night	3 18% 10% 17% 10% 6% 5% 4 6% 6% 15%	1900
	11th to 20th	Night	3 16% 6% 13% 8% 7% 5% 5% 6% 7% 24%	1742
	21st to end	Night	6% 19% 5% 11% 6% 6% 5% 5% 6% 6% 25%	1585
May	1st to 10th	Night	6% 22% 5% 11% 7% 5% 4 3 7% 8% 22%	2540
	11th to 20th	Night	11% 20% 5% 9% 4 5% 4 4 6% 6% 24%	2295
	21st to end	Night	14% 24% 5% 13% 6% 5% 5% 3 4 5% 16%	2414
June	1st to 10th	Night	16% 14% 3 9% 8% 4 5% 5% 5% 6% 26%	1166
	11th to 20th	Night	19% 13% 4 8% 8% 6% 6% 6% 6% 8% 17%	1140
	21st to end	Night	13% 10% 4 8% 6% 6% 6% 6% 8% 6% 29%	1140
July	1st to 10th	Night	15% 9% 2 6% 4 4 4 3 4 6% 42%	1900
	11th to 20th	Night	11% 6% 2 4 3 4 4 4 6% 7% 50%	1983
	21st to end	Night	18% 8% 3 6% 5% 4 4 4 5% 8% 36%	2696
August	1st to 10th	Night	12% 8% 3 7% 5% 5% 4 4 6% 9% 37%	2529
	11th to 20th	Night	14% 8% 3 8% 6% 5% 6% 4 6% 8% 32%	2497
	21st to end	Night	17% 11% 2 7% 5% 4 5% 4 6% 7% 32%	3202
September	1st to 10th	Night	14% 10% 3 7% 4 4 4 4 6% 7% 36%	1900
	11th to 20th	Night	14% 12% 3 8% 5% 4 4 3 5% 6% 36%	1976
	21st to end	Night	12% 13% 3 8% 5% 6% 5% 4 6% 7% 30%	2090
October	1st to 10th	Night	8% 18% 5% 9% 5% 5% 6% 5% 7% 7% 26%	2225
	11th to 20th	Night	8% 17% 6% 11% 5% 6% 5% 4 6% 7% 23%	2441
	21st to end	Night	6% 19% 8% 15% 8% 5% 5% 3 4 7% 20%	2717
November	1st to 10th	Night	7% 18% 9% 14% 8% 8% 6% 4 6% 5% 15%	2510
	11th to 20th	Night	3 15% 7% 15% 10% 7% 6% 5% 7% 7% 17%	2848
	21st to end	Night	3 17% 7% 15% 9% 8% 6% 5% 5% 6% 18%	2850
December	1st to 10th	Night	4 14% 7% 17% 8% 7% 6% 5% 5% 6% 20%	2850
	11th to 20th	Night	3 17% 9% 17% 11% 7% 6% 4 7% 7% 12%	3689
	21st to end	Night	1 16% 6% 13% 7% 6% 6% 5% 8% 9% 23%	5566

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	71% 6% 9% 9% 2 1	1899
	11th to 20th	Day	59% 6% 6% 8% 12% 8%	2282
	21st to end	Day	70% 7% 12% 7% 4	2794
February	1st to 10th	Day	68% 6% 8% 7% 8% 2	1520
	11th to 20th	Day	69% 6% 8% 12% 5% 1	1560
	21st to end	Day	66% 6% 9% 12% 5% 2	1570
March	1st to 10th	Day	66% 7% 7% 11% 9%	3138
	11th to 20th	Day	60% 7% 11% 17% 5%	3242
	21st to end	Day	67% 7% 8% 10% 6% 1	4158
April	1st to 10th	Day	77% 6% 8% 7% 1	2280
	11th to 20th	Day	69% 7% 10% 11% 2	2389
	21st to end	Day	70% 7% 9% 12% 2	2593
May	1st to 10th	Day	64% 5% 13% 13% 4	4420
	11th to 20th	Day	63% 7% 12% 14% 5%	4602
	21st to end	Day	74% 5% 10% 8% 3	5162
June	1st to 10th	Day	66% 7% 10% 12% 4 1	3011
	11th to 20th	Day	72% 6% 11% 8% 2	3040
	21st to end	Day	64% 6% 14% 12% 4 1	3040
July	1st to 10th	Day	50% 5% 9% 17% 15% 4	4981
	11th to 20th	Day	43% 6% 12% 23% 15% 1	4887
	21st to end	Day	54% 6% 10% 16% 12% 3	4700
August	1st to 10th	Day	50% 6% 13% 24% 7%	4384
	11th to 20th	Day	54% 8% 14% 19% 5%	4372
	21st to end	Day	57% 5% 13% 20% 4	4463
September	1st to 10th	Day	56% 5% 13% 19% 5% 1	2280
	11th to 20th	Day	54% 5% 15% 16% 9%	2204
	21st to end	Day	60% 6% 13% 14% 6% 1	2090
October	1st to 10th	Day	60% 6% 13% 16% 5%	1952
	11th to 20th	Day	61% 9% 13% 15% 1	1738
	21st to end	Day	64% 8% 11% 12% 5%	1881
November	1st to 10th	Day	71% 7% 10% 8% 4 1	1556
	11th to 20th	Day	59% 10% 15% 9% 5% 1	1330
	21st to end	Day	62% 8% 14% 7% 4 4	1330
December	1st to 10th	Day	66% 7% 6% 13% 7% 1	1330
	11th to 20th	Day	67% 6% 9% 11% 5% 2	1501
	21st to end	Day	56% 6% 12% 14% 11%	2090
January	1st to 10th	Night	72% 9% 8% 6% 5% 2	5046
	11th to 20th	Night	56% 6% 6% 10% 17% 5%	4708
	21st to end	Night	74% 5% 7% 9% 4 1	4862
February	1st to 10th	Night	69% 6% 8% 7% 7% 3	2660
	11th to 20th	Night	66% 8% 9% 9% 6% 1	2511
	21st to end	Night	59% 7% 9% 16% 7% 2	1884
March	1st to 10th	Night	64% 7% 8% 13% 8% 1	3736
	11th to 20th	Night	56% 8% 14% 18% 4	3738
	21st to end	Night	63% 6% 11% 12% 7%	3493
April	1st to 10th	Night	69% 8% 11% 10% 2	1900
	11th to 20th	Night	59% 6% 16% 14% 5%	1742
	21st to end	Night	60% 8% 12% 15% 4 1	1585
May	1st to 10th	Night	60% 7% 14% 16% 3	2540
	11th to 20th	Night	58% 9% 12% 15% 7%	2295
	21st to end	Night	70% 6% 11% 10% 3	2414
June	1st to 10th	Night	56% 8% 17% 12% 6% 1	1166
	11th to 20th	Night	65% 9% 13% 11% 3	1140
	21st to end	Night	52% 8% 20% 15% 5% 1	1140
July	1st to 10th	Night	45% 4 12% 19% 19% 1	1870
	11th to 20th	Night	34% 6% 12% 26% 22%	1947
	21st to end	Night	46% 5% 14% 22% 9% 4	2611
August	1st to 10th	Night	40% 9% 16% 31% 3	2521
	11th to 20th	Night	45% 10% 21% 20% 4	2521
	21st to end	Night	50% 8% 22% 16% 4	3202
September	1st to 10th	Night	47% 6% 18% 22% 6% 1	1900
	11th to 20th	Night	50% 6% 16% 19% 8%	1976
	21st to end	Night	52% 9% 15% 16% 6% 1	2090
October	1st to 10th	Night	55% 8% 16% 17% 3	2225
	11th to 20th	Night	59% 9% 13% 16% 3	2441
	21st to end	Night	65% 7% 12% 11% 5%	2717
November	1st to 10th	Night	71% 7% 10% 7% 4 1	2510
	11th to 20th	Night	64% 11% 10% 8% 6% 1	2848
	21st to end	Night	65% 9% 10% 9% 5% 3	2850
December	1st to 10th	Night	64% 7% 8% 10% 9% 1	2850
	11th to 20th	Night	68% 8% 9% 9% 4 1	3686
	21st to end	Night	56% 9% 12% 14% 7% 1	5566

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	13% 22% 34% 22% 7% 1	180
	11th to 20th	Day	17% 22% 32% 23% 4 3	180
	21st to end	Day	19% 23% 38% 13% 4 2	198
February	1st to 10th	Day	24% 21% 36% 14% 5% 1	180
	11th to 20th	Day	15% 23% 34% 19% 7% 2	252
	21st to end	Day	15% 25% 35% 17% 7% 1	382
March	1st to 10th	Day	18% 25% 32% 15% 9% 2	460
	11th to 20th	Day	17% 29% 30% 17% 5% 2	460
	21st to end	Day	18% 27% 29% 18% 6% 2	506
April	1st to 10th	Day	27% 21% 30% 15% 5% 1	460
	11th to 20th	Day	17% 23% 31% 21% 7% 2	452
	21st to end	Day	23% 24% 24% 18% 8% 2	460
May	1st to 10th	Day	23% 16% 34% 18% 7% 2	463
	11th to 20th	Day	16% 14% 25% 29% 13% 3	618
	21st to end	Day	22% 12% 23% 24% 15% 3	734
June	1st to 10th	Day	25% 17% 30% 19% 7% 1	841
	11th to 20th	Day	29% 16% 28% 18% 8% 1	870
	21st to end	Day	23% 13% 26% 23% 12% 2	870
July	1st to 10th	Day	23% 13% 26% 25% 13% 1	856
	11th to 20th	Day	22% 13% 30% 24% 9% 2	805
	21st to end	Day	19% 14% 29% 24% 11% 3	568
August	1st to 10th	Day	21% 10% 31% 24% 11% 4	487
	11th to 20th	Day	20% 19% 35% 17% 8% 1	477
	21st to end	Day	27% 17% 31% 17% 7% 1	539
September	1st to 10th	Day	29% 18% 28% 18% 7% 1	490
	11th to 20th	Day	25% 22% 27% 21% 4 2	490
	21st to end	Day	37% 26% 19% 14% 4 1	490
October	1st to 10th	Day	30% 21% 25% 16% 7% 2	490
	11th to 20th	Day	30% 24% 26% 15% 4 2	328
	21st to end	Day	25% 19% 31% 18% 5%	330
November	1st to 10th	Day	29% 24% 28% 12% 5% 2	223
	11th to 20th	Day	23% 26% 33% 13% 4 1	180
	21st to end	Day	21% 26% 25% 18% 7% 3	180
December	1st to 10th	Day	14% 26% 28% 21% 7% 4	180
	11th to 20th	Day	15% 28% 34% 17% 4 1	180
	21st to end	Day	10% 20% 37% 23% 9% 2	198
January	1st to 10th	Night	12% 21% 44% 17% 4 1	1040
	11th to 20th	Night	11% 22% 44% 17% 4 1	891
	21st to end	Night	13% 25% 40% 16% 5% 1	836
February	1st to 10th	Night	14% 20% 35% 24% 6% 1	760
	11th to 20th	Night	10% 19% 41% 23% 6% 1	744
	21st to end	Night	10% 13% 38% 27% 10% 1	628
March	1st to 10th	Night	7% 19% 42% 22% 9% 1	760
	11th to 20th	Night	7% 23% 42% 21% 7% 1	760
	21st to end	Night	8% 16% 34% 30% 12% 1	836
April	1st to 10th	Night	10% 19% 31% 30% 9% 1	760
	11th to 20th	Night	8% 14% 39% 25% 13% 1	614
	21st to end	Night	15% 14% 29% 31% 9% 1	445
May	1st to 10th	Night	17% 9% 23% 34% 15% 1	380
	11th to 20th	Night	10% 9% 24% 35% 20% 2	374
	21st to end	Night	19% 10% 22% 26% 21% 2	411
June	1st to 10th	Night	21% 6% 33% 25% 14% 1	380
	11th to 20th	Night	24% 9% 27% 25% 14%	380
	21st to end	Night	17% 8% 24% 30% 19% 1	380
July	1st to 10th	Night	20% 5% 23% 37% 15% 1	370
	11th to 20th	Night	20% 8% 22% 33% 16%	368
	21st to end	Night	15% 7% 20% 39% 19%	416
August	1st to 10th	Night	16% 4 18% 37% 23% 2	378
	11th to 20th	Night	15% 8% 20% 36% 19% 1	376
	21st to end	Night	21% 11% 29% 28% 11% 1	657
September	1st to 10th	Night	20% 10% 30% 26% 13% 1	760
	11th to 20th	Night	19% 12% 26% 27% 15% 2	760
	21st to end	Night	23% 16% 29% 22% 9% 2	760
October	1st to 10th	Night	18% 16% 33% 24% 9% 1	760
	11th to 20th	Night	18% 16% 36% 23% 6% 1	760
	21st to end	Night	16% 18% 41% 19% 5%	836
November	1st to 10th	Night	16% 23% 41% 15% 5%	742
	11th to 20th	Night	15% 24% 44% 14% 3 1	948
	21st to end	Night	15% 21% 43% 16% 4 2	950
December	1st to 10th	Night	12% 22% 41% 18% 6%	950
	11th to 20th	Night	10% 23% 44% 16% 6%	1011
	21st to end	Night	9% 19% 47% 19% 6% 1	1144

Page generated at 2024-10-29 09:20:51. Version ac07

Copyright © 2024 Attilla Danko.