Jasper Marmot Meadows
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Jasper Marmot Meadows clear sky chart from 2005-11-06 to 2024-02-25.

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	8% 11% 6% 11% 9% 5% 7% 6% 7% 8% 24%	77673
	Night	4 9% 5% 10% 9% 5% 7% 7% 8% 9% 28%	81562
Transparency	Day	58% 9% 15% 13% 5% 1	77372
	Night	52% 10% 17% 14% 5% 1	81443
Seeing	Day	19% 13% 28% 25% 12% 3	15009
	Night	11% 10% 35% 31% 11% 1	23584

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	1 6% 9% 14% 12% 8% 9% 7% 9% 10% 16%	1899
	11th to 20th	Day	1 7% 5% 15% 7% 4 6% 7% 9% 8% 32%	2190
	21st to end	Day	1 15% 5% 11% 11% 5% 8% 7% 8% 10% 17%	2794
February	1st to 10th	Day	2 8% 7% 14% 10% 6% 8% 7% 8% 8% 22%	1520
	11th to 20th	Day	1 9% 6% 15% 11% 5% 8% 7% 8% 8% 22%	1564
	21st to end	Day	1 6% 5% 14% 14% 7% 8% 7% 7% 8% 22%	1506
March	1st to 10th	Day	8% 6% 11% 12% 7% 9% 8% 9% 9% 20%	1800
	11th to 20th	Day	1 7% 7% 13% 9% 6% 8% 7% 8% 9% 25%	1832
	21st to end	Day	1 13% 8% 16% 13% 5% 8% 7% 7% 7% 14%	2376
April	1st to 10th	Day	3 13% 9% 16% 12% 7% 8% 7% 5% 6% 14%	2160
	11th to 20th	Day	5% 14% 8% 15% 12% 5% 6% 6% 5% 6% 19%	2249
	21st to end	Day	7% 16% 6% 13% 10% 4 6% 5% 6% 7% 20%	2477
May	1st to 10th	Day	9% 19% 8% 11% 9% 4 5% 5% 6% 7% 18%	2520
	11th to 20th	Day	9% 13% 4 10% 8% 5% 7% 5% 6% 8% 27%	2584
	21st to end	Day	16% 15% 6% 9% 8% 4 6% 5% 5% 5% 21%	2925
June	1st to 10th	Day	18% 12% 5% 10% 8% 4 6% 6% 6% 6% 18%	2880
	11th to 20th	Day	20% 16% 6% 11% 9% 4 6% 6% 5% 5% 12%	2880
	21st to end	Day	13% 12% 5% 10% 10% 5% 6% 6% 6% 6% 21%	2880
July	1st to 10th	Day	15% 10% 5% 8% 8% 4 7% 6% 6% 7% 24%	2880
	11th to 20th	Day	12% 9% 4 8% 8% 5% 7% 6% 7% 7% 26%	2872
	21st to end	Day	9% 8% 5% 10% 9% 4 7% 6% 6% 7% 31%	2762
August	1st to 10th	Day	11% 10% 4 7% 9% 4 7% 6% 6% 7% 28%	2507
	11th to 20th	Day	10% 8% 4 7% 7% 5% 6% 5% 6% 8% 33%	2475
	21st to end	Day	13% 11% 4 8% 7% 4 6% 6% 6% 8% 27%	2545
September	1st to 10th	Day	11% 12% 4 9% 7% 5% 6% 5% 5% 6% 31%	2160
	11th to 20th	Day	11% 10% 4 7% 6% 5% 5% 6% 6% 6% 34%	2102
	21st to end	Day	8% 12% 5% 10% 9% 5% 6% 4 6% 6% 29%	1980
October	1st to 10th	Day	6% 14% 5% 9% 9% 4 5% 6% 7% 8% 28%	1832
	11th to 20th	Day	5% 11% 4 10% 8% 5% 7% 8% 7% 9% 26%	1658
	21st to end	Day	3 11% 5% 11% 10% 5% 7% 8% 6% 8% 25%	1782
November	1st to 10th	Day	3 12% 5% 14% 11% 6% 7% 6% 7% 7% 22%	1550
	11th to 20th	Day	2 6% 6% 10% 8% 5% 7% 8% 8% 11% 30%	1330
	21st to end	Day	2 9% 6% 11% 10% 6% 7% 7% 7% 9% 27%	1330
December	1st to 10th	Day	2 7% 5% 12% 11% 5% 8% 7% 9% 7% 25%	1330
	11th to 20th	Day	2 9% 5% 10% 9% 7% 9% 9% 8% 10% 24%	1452
	21st to end	Day	8% 4 9% 7% 4 7% 7% 8% 13% 33%	2090
January	1st to 10th	Night	1 6% 7% 15% 14% 6% 8% 6% 7% 9% 20%	5046
	11th to 20th	Night	1 7% 5% 10% 9% 5% 8% 8% 10% 11% 28%	4735
	21st to end	Night	1 12% 5% 11% 10% 6% 8% 7% 8% 10% 20%	4862
February	1st to 10th	Night	3 10% 6% 12% 12% 6% 8% 8% 9% 8% 20%	2660
	11th to 20th	Night	1 8% 5% 11% 10% 6% 9% 7% 8% 10% 24%	2498
	21st to end	Night	1 8% 6% 11% 10% 5% 9% 7% 8% 10% 24%	1844
March	1st to 10th	Night	8% 5% 12% 11% 5% 7% 8% 8% 9% 26%	2160
	11th to 20th	Night	1 7% 5% 9% 9% 5% 8% 8% 9% 10% 29%	2124
	21st to end	Night	1 11% 6% 13% 9% 5% 7% 7% 7% 10% 21%	1980
April	1st to 10th	Night	2 11% 7% 13% 11% 6% 7% 7% 8% 8% 21%	1800
	11th to 20th	Night	3 10% 6% 10% 10% 4 6% 6% 7% 9% 28%	1661
	21st to end	Night	6% 11% 5% 11% 7% 3 7% 7% 6% 8% 29%	1481
May	1st to 10th	Night	8% 12% 4 9% 8% 4 6% 8% 8% 7% 27%	1440
	11th to 20th	Night	6% 8% 3 8% 6% 5% 6% 6% 7% 8% 37%	1307
	21st to end	Night	12% 11% 5% 7% 8% 4 6% 6% 5% 9% 29%	1346
June	1st to 10th	Night	14% 9% 5% 8% 5% 6% 6% 6% 6% 8% 28%	1080
	11th to 20th	Night	17% 13% 5% 8% 9% 4 8% 6% 6% 6% 19%	1080
	21st to end	Night	9% 6% 3 8% 7% 4 8% 7% 7% 10% 31%	1080
July	1st to 10th	Night	13% 7% 3 4 6% 4 6% 6% 8% 10% 34%	1080
	11th to 20th	Night	11% 6% 2 7% 7% 4 7% 6% 8% 9% 33%	1088
	21st to end	Night	7% 6% 3 7% 6% 4 6% 6% 5% 8% 43%	1552
August	1st to 10th	Night	9% 7% 3 7% 7% 3 6% 7% 7% 9% 35%	1432
	11th to 20th	Night	10% 6% 3 6% 5% 4 4 5% 6% 8% 43%	1424
	21st to end	Night	13% 7% 3 6% 6% 3 6% 7% 6% 8% 35%	1808
September	1st to 10th	Night	11% 9% 3 7% 6% 4 6% 5% 6% 8% 36%	1800
	11th to 20th	Night	10% 10% 4 7% 6% 4 5% 5% 6% 7% 36%	1858
	21st to end	Night	7% 9% 4 8% 7% 4 6% 6% 7% 9% 33%	1980
October	1st to 10th	Night	5% 13% 4 10% 8% 4 6% 6% 6% 8% 30%	2126
	11th to 20th	Night	5% 11% 4 8% 8% 5% 6% 7% 8% 10% 30%	2301
	21st to end	Night	3 11% 5% 10% 9% 5% 7% 6% 9% 8% 26%	2574
November	1st to 10th	Night	3 12% 6% 11% 10% 6% 7% 7% 7% 8% 23%	2522
	11th to 20th	Night	1 8% 5% 9% 8% 5% 8% 8% 8% 11% 28%	2832
	21st to end	Night	1 8% 6% 10% 10% 6% 8% 7% 8% 11% 26%	2850
December	1st to 10th	Night	3 7% 5% 11% 10% 5% 6% 8% 7% 10% 28%	2850
	11th to 20th	Night	1 8% 6% 11% 11% 6% 9% 8% 9% 10% 22%	3735
	21st to end	Night	1 7% 4 9% 8% 5% 7% 7% 8% 11% 33%	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	62% 11% 17% 8% 3	1899
	11th to 20th	Day	49% 10% 13% 10% 15% 3	2211
	21st to end	Day	60% 12% 17% 7% 3	2794
February	1st to 10th	Day	58% 9% 13% 10% 8% 2	1520
	11th to 20th	Day	61% 7% 12% 14% 5%	1572
	21st to end	Day	58% 8% 13% 13% 6% 2	1506
March	1st to 10th	Day	56% 11% 16% 12% 5%	1800
	11th to 20th	Day	56% 9% 16% 14% 5%	1832
	21st to end	Day	69% 8% 12% 8% 3	2376
April	1st to 10th	Day	72% 7% 13% 7% 1	2160
	11th to 20th	Day	65% 7% 15% 12% 2	2249
	21st to end	Day	64% 9% 14% 11% 2	2477
May	1st to 10th	Day	66% 7% 13% 11% 2	2520
	11th to 20th	Day	55% 7% 16% 15% 7%	2588
	21st to end	Day	64% 8% 13% 11% 4	2926
June	1st to 10th	Day	65% 8% 11% 11% 4 1	2880
	11th to 20th	Day	73% 7% 10% 7% 3	2880
	21st to end	Day	62% 8% 13% 11% 5% 1	2880
July	1st to 10th	Day	55% 10% 12% 16% 5% 1	2801
	11th to 20th	Day	57% 8% 14% 15% 6%	2785
	21st to end	Day	51% 8% 14% 19% 7%	2608
August	1st to 10th	Day	54% 9% 16% 15% 6%	2490
	11th to 20th	Day	49% 7% 17% 19% 6% 1	2475
	21st to end	Day	54% 7% 13% 19% 6%	2545
September	1st to 10th	Day	55% 6% 15% 20% 4 1	2160
	11th to 20th	Day	49% 7% 17% 18% 8% 1	2102
	21st to end	Day	56% 8% 14% 14% 7% 1	1980
October	1st to 10th	Day	54% 8% 17% 17% 4	1832
	11th to 20th	Day	55% 12% 16% 16% 2	1658
	21st to end	Day	58% 9% 15% 14% 4	1782
November	1st to 10th	Day	61% 10% 15% 10% 3 1	1550
	11th to 20th	Day	49% 13% 22% 11% 5% 1	1330
	21st to end	Day	53% 12% 19% 9% 5% 2	1330
December	1st to 10th	Day	57% 9% 13% 14% 6% 1	1330
	11th to 20th	Day	57% 10% 16% 11% 5% 1	1454
	21st to end	Day	43% 10% 24% 14% 8%	2090
January	1st to 10th	Night	61% 9% 17% 9% 4 1	5046
	11th to 20th	Night	49% 10% 10% 13% 16% 2	4776
	21st to end	Night	62% 12% 13% 10% 3	4862
February	1st to 10th	Night	61% 9% 12% 9% 7% 1	2660
	11th to 20th	Night	56% 9% 17% 12% 5% 1	2500
	21st to end	Night	52% 7% 15% 17% 7% 1	1844
March	1st to 10th	Night	53% 10% 16% 14% 6% 1	2160
	11th to 20th	Night	49% 9% 21% 17% 5%	2125
	21st to end	Night	55% 11% 18% 11% 4	1980
April	1st to 10th	Night	60% 9% 18% 12% 2	1800
	11th to 20th	Night	51% 10% 19% 15% 4	1661
	21st to end	Night	52% 11% 15% 17% 4	1481
May	1st to 10th	Night	53% 11% 17% 16% 3	1440
	11th to 20th	Night	42% 12% 18% 19% 9%	1307
	21st to end	Night	53% 10% 16% 17% 4	1346
June	1st to 10th	Night	53% 7% 17% 15% 6% 1	1080
	11th to 20th	Night	64% 8% 16% 9% 3	1080
	21st to end	Night	47% 11% 22% 15% 5% 1	1080
July	1st to 10th	Night	42% 10% 20% 22% 6% 1	1050
	11th to 20th	Night	46% 10% 21% 16% 7% 1	1052
	21st to end	Night	37% 9% 21% 25% 7%	1466
August	1st to 10th	Night	43% 9% 23% 21% 4	1424
	11th to 20th	Night	40% 8% 23% 23% 6%	1424
	21st to end	Night	44% 9% 20% 20% 7%	1808
September	1st to 10th	Night	45% 8% 20% 21% 6% 1	1800
	11th to 20th	Night	47% 7% 19% 18% 8% 1	1858
	21st to end	Night	46% 11% 20% 17% 5% 1	1980
October	1st to 10th	Night	51% 10% 18% 18% 3	2126
	11th to 20th	Night	51% 11% 18% 18% 2	2301
	21st to end	Night	55% 10% 17% 13% 5%	2574
November	1st to 10th	Night	61% 10% 17% 10% 3	2522
	11th to 20th	Night	52% 13% 19% 9% 5%	2832
	21st to end	Night	54% 12% 17% 10% 5% 2	2850
December	1st to 10th	Night	54% 9% 17% 13% 7% 1	2850
	11th to 20th	Night	58% 12% 16% 10% 4	3732
	21st to end	Night	46% 9% 23% 17% 4 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	9% 7% 19% 44% 17% 3	180
	11th to 20th	Day	9% 7% 26% 38% 16% 4	180
	21st to end	Day	16% 6% 32% 30% 12% 5%	198
February	1st to 10th	Day	18% 11% 29% 29% 11% 3	180
	11th to 20th	Day	16% 13% 28% 25% 14% 5%	264
	21st to end	Day	10% 18% 37% 21% 12% 2	356
March	1st to 10th	Day	14% 23% 30% 18% 12% 3	420
	11th to 20th	Day	15% 20% 33% 19% 9% 3	420
	21st to end	Day	16% 20% 30% 20% 10% 5%	462
April	1st to 10th	Day	19% 20% 31% 22% 7% 1	420
	11th to 20th	Day	17% 16% 29% 23% 9% 6%	412
	21st to end	Day	20% 19% 25% 21% 10% 4	420
May	1st to 10th	Day	23% 13% 30% 22% 9% 2	423
	11th to 20th	Day	17% 11% 25% 29% 14% 3	555
	21st to end	Day	22% 10% 21% 24% 19% 3	687
June	1st to 10th	Day	23% 13% 31% 23% 10% 1	810
	11th to 20th	Day	30% 12% 25% 23% 9% 1	810
	21st to end	Day	19% 13% 25% 25% 15% 3	810
July	1st to 10th	Day	20% 10% 27% 29% 12% 2	796
	11th to 20th	Day	20% 10% 28% 27% 11% 3	784
	21st to end	Day	15% 12% 27% 25% 17% 4	508
August	1st to 10th	Day	18% 9% 25% 28% 16% 5%	447
	11th to 20th	Day	16% 14% 33% 21% 12% 4	437
	21st to end	Day	21% 12% 31% 22% 12% 3	495
September	1st to 10th	Day	26% 13% 28% 18% 13% 3	450
	11th to 20th	Day	19% 14% 27% 25% 13% 2	450
	21st to end	Day	26% 21% 26% 16% 8% 3	450
October	1st to 10th	Day	20% 14% 30% 20% 11% 5%	450
	11th to 20th	Day	20% 14% 28% 22% 12% 3	308
	21st to end	Day	19% 9% 28% 34% 8% 2	297
November	1st to 10th	Day	20% 13% 31% 25% 8% 3	212
	11th to 20th	Day	17% 9% 31% 30% 9% 4	180
	21st to end	Day	18% 14% 23% 28% 11% 7%	180
December	1st to 10th	Day	12% 6% 26% 31% 18% 8%	180
	11th to 20th	Day	10% 6% 24% 40% 14% 6%	180
	21st to end	Day	8% 7% 21% 40% 17% 8%	198
January	1st to 10th	Night	9% 13% 38% 32% 6% 1	1040
	11th to 20th	Night	7% 14% 41% 29% 7% 2	898
	21st to end	Night	9% 15% 44% 24% 7% 1	836
February	1st to 10th	Night	12% 11% 38% 28% 11% 1	760
	11th to 20th	Night	8% 10% 39% 33% 9% 1	744
	21st to end	Night	8% 10% 39% 30% 11% 3	610
March	1st to 10th	Night	6% 13% 41% 27% 11% 2	720
	11th to 20th	Night	5% 13% 44% 27% 10% 1	720
	21st to end	Night	7% 12% 36% 32% 12% 3	792
April	1st to 10th	Night	8% 12% 31% 36% 12% 1	720
	11th to 20th	Night	9% 12% 34% 30% 15% 1	593
	21st to end	Night	15% 7% 30% 34% 13%	401
May	1st to 10th	Night	13% 6% 23% 45% 13%	360
	11th to 20th	Night	11% 3 28% 41% 16% 1	354
	21st to end	Night	19% 5% 23% 30% 22% 1	389
June	1st to 10th	Night	20% 3 31% 31% 14% 1	360
	11th to 20th	Night	23% 6% 23% 33% 14% 2	360
	21st to end	Night	15% 7% 23% 34% 21% 2	360
July	1st to 10th	Night	17% 5% 19% 41% 17% 1	350
	11th to 20th	Night	17% 7% 22% 32% 22% 1	348
	21st to end	Night	11% 3 19% 43% 23% 1	394
August	1st to 10th	Night	15% 2 15% 39% 28% 1	358
	11th to 20th	Night	15% 3 21% 39% 21% 2	356
	21st to end	Night	17% 6% 25% 39% 12% 1	620
September	1st to 10th	Night	18% 7% 25% 35% 15% 1	720
	11th to 20th	Night	17% 5% 26% 33% 18% 1	720
	21st to end	Night	18% 12% 32% 27% 12% 1	720
October	1st to 10th	Night	15% 9% 30% 35% 10% 1	720
	11th to 20th	Night	13% 11% 38% 28% 9% 1	720
	21st to end	Night	14% 13% 40% 26% 7%	792
November	1st to 10th	Night	12% 13% 41% 28% 5% 1	740
	11th to 20th	Night	11% 16% 41% 27% 4 1	932
	21st to end	Night	9% 13% 45% 24% 7% 1	950
December	1st to 10th	Night	8% 12% 41% 29% 9% 1	950
	11th to 20th	Night	8% 10% 44% 28% 8% 1	1033
	21st to end	Night	5% 10% 43% 30% 10% 1	1144

Page generated at 2024-02-22 04:05:48. Version ac07

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