Kluane Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kluane Lake clear sky chart from 2005-11-06 to 2024-07-08.

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	6% 7% 3 9% 7% 7% 7% 6% 8% 11% 30%	89152
	Night	3 8% 4 11% 8% 7% 8% 6% 9% 11% 26%	90182
Transparency	Day	44% 16% 17% 16% 7% 1	88800
	Night	43% 15% 15% 16% 9% 2	90115
Seeing	Day	10% 11% 26% 28% 19% 6%	16601
	Night	7% 8% 25% 32% 22% 6%	22446

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	3 1 10% 9% 10% 10% 7% 10% 11% 28%	1551
	11th to 20th	Day	1 6% 3 12% 11% 9% 7% 6% 11% 10% 24%	1565
	21st to end	Day	4 2 8% 8% 10% 13% 9% 10% 11% 26%	2094
February	1st to 10th	Day	1 4 4 7% 7% 8% 8% 6% 8% 12% 35%	1330
	11th to 20th	Day	1 5% 4 9% 7% 5% 7% 6% 9% 12% 33%	1439
	21st to end	Day	4 4 10% 9% 10% 8% 7% 8% 9% 31%	1413
March	1st to 10th	Day	3 2 10% 12% 12% 8% 6% 8% 10% 29%	2922
	11th to 20th	Day	4 3 8% 8% 7% 8% 6% 10% 12% 33%	3467
	21st to end	Day	3 2 6% 6% 6% 7% 7% 10% 16% 37%	3988
April	1st to 10th	Day	7% 4 11% 6% 5% 6% 6% 9% 12% 32%	2418
	11th to 20th	Day	2 10% 4 9% 6% 6% 6% 6% 8% 9% 35%	2550
	21st to end	Day	1 7% 4 8% 5% 6% 7% 6% 8% 10% 37%	2739
May	1st to 10th	Day	1 5% 2 9% 6% 6% 6% 6% 9% 12% 37%	4928
	11th to 20th	Day	3 8% 3 8% 5% 6% 7% 6% 8% 12% 33%	5040
	21st to end	Day	6% 8% 3 7% 5% 6% 6% 6% 9% 11% 32%	5879
June	1st to 10th	Day	10% 8% 3 7% 6% 6% 6% 5% 8% 10% 31%	3420
	11th to 20th	Day	14% 10% 3 9% 7% 6% 6% 5% 7% 9% 24%	3420
	21st to end	Day	11% 7% 3 8% 7% 6% 8% 6% 9% 9% 26%	3420
July	1st to 10th	Day	12% 7% 3 8% 7% 6% 7% 6% 8% 9% 27%	3315
	11th to 20th	Day	14% 9% 3 8% 7% 7% 7% 5% 8% 11% 21%	3060
	21st to end	Day	14% 8% 3 7% 5% 5% 6% 5% 8% 9% 29%	3268
August	1st to 10th	Day	12% 7% 3 6% 5% 5% 6% 5% 7% 10% 33%	2740
	11th to 20th	Day	10% 9% 3 8% 6% 7% 6% 7% 7% 8% 29%	2619
	21st to end	Day	14% 9% 3 8% 7% 7% 7% 6% 7% 9% 24%	2693
September	1st to 10th	Day	9% 9% 4 8% 7% 7% 7% 4 7% 9% 29%	2278
	11th to 20th	Day	6% 8% 3 7% 6% 5% 6% 6% 8% 10% 35%	2156
	21st to end	Day	6% 13% 3 8% 5% 6% 6% 5% 7% 10% 30%	1898
October	1st to 10th	Day	6% 10% 3 8% 7% 6% 7% 7% 8% 9% 30%	1800
	11th to 20th	Day	3 10% 5% 11% 7% 7% 6% 5% 7% 9% 30%	1581
	21st to end	Day	2 13% 5% 11% 6% 9% 9% 6% 8% 8% 24%	1584
November	1st to 10th	Day	1 9% 7% 15% 8% 7% 7% 6% 7% 10% 23%	1264
	11th to 20th	Day	1 8% 5% 14% 14% 9% 9% 8% 11% 7% 14%	1140
	21st to end	Day	1 6% 4 12% 5% 9% 11% 9% 11% 14% 19%	1065
December	1st to 10th	Day	1 6% 6% 12% 7% 8% 8% 10% 11% 11% 19%	760
	11th to 20th	Day	4 2 10% 7% 6% 8% 8% 11% 11% 32%	962
	21st to end	Day	5% 3 9% 6% 7% 9% 8% 11% 14% 28%	1386
January	1st to 10th	Night	5% 3 9% 8% 8% 8% 6% 10% 13% 30%	5422
	11th to 20th	Night	7% 5% 11% 9% 7% 8% 7% 9% 11% 26%	5333
	21st to end	Night	4 3 10% 8% 9% 11% 9% 11% 11% 23%	5566
February	1st to 10th	Night	1 6% 3 10% 9% 8% 8% 6% 10% 13% 27%	2850
	11th to 20th	Night	5% 3 10% 7% 6% 9% 7% 10% 13% 28%	2626
	21st to end	Night	6% 3 13% 10% 8% 9% 7% 9% 11% 24%	2041
March	1st to 10th	Night	5% 4 14% 11% 11% 9% 7% 9% 10% 20%	3942
	11th to 20th	Night	1 9% 4 12% 9% 9% 8% 6% 8% 11% 24%	3489
	21st to end	Night	1 5% 3 13% 8% 7% 7% 6% 9% 14% 27%	3648
April	1st to 10th	Night	1 8% 5% 13% 6% 6% 6% 4 8% 12% 31%	1762
	11th to 20th	Night	1 11% 5% 9% 6% 5% 7% 5% 9% 9% 33%	1579
	21st to end	Night	2 9% 5% 9% 6% 5% 5% 6% 8% 10% 34%	1439
May	1st to 10th	Night	2 6% 2 8% 6% 6% 7% 7% 9% 14% 34%	2036
	11th to 20th	Night	5% 9% 3 7% 6% 5% 6% 6% 7% 9% 38%	1853
	21st to end	Night	10% 11% 4 8% 6% 6% 7% 4 7% 9% 28%	1695
June	1st to 10th	Night	11% 6% 3 7% 6% 6% 6% 7% 8% 10% 30%	760
	11th to 20th	Night	16% 10% 4 9% 6% 6% 5% 4 8% 8% 25%	760
	21st to end	Night	13% 8% 3 6% 6% 7% 9% 5% 9% 13% 21%	760
July	1st to 10th	Night	15% 8% 2 8% 6% 7% 6% 4 7% 7% 29%	807
	11th to 20th	Night	17% 9% 3 10% 7% 5% 6% 5% 6% 9% 22%	900
	21st to end	Night	18% 9% 2 7% 4 5% 4 5% 7% 9% 29%	1049
August	1st to 10th	Night	13% 6% 3 8% 6% 5% 6% 5% 9% 10% 31%	1199
	11th to 20th	Night	12% 8% 3 8% 5% 6% 6% 5% 7% 9% 31%	1281
	21st to end	Night	14% 10% 3 8% 5% 7% 7% 7% 8% 9% 23%	1660
September	1st to 10th	Night	11% 9% 3 8% 6% 5% 6% 5% 8% 8% 31%	1682
	11th to 20th	Night	7% 7% 3 7% 5% 6% 6% 6% 8% 9% 37%	1804
	21st to end	Night	8% 15% 3 7% 5% 6% 6% 5% 8% 7% 29%	2061
October	1st to 10th	Night	6% 12% 4 11% 6% 6% 7% 5% 6% 8% 30%	2160
	11th to 20th	Night	5% 15% 6% 14% 6% 6% 6% 4 6% 8% 24%	2377
	21st to end	Night	3 11% 6% 14% 9% 9% 9% 5% 7% 7% 21%	2772
November	1st to 10th	Night	1 11% 5% 12% 10% 8% 8% 6% 8% 11% 19%	2813
	11th to 20th	Night	1 9% 6% 16% 12% 8% 8% 5% 8% 10% 16%	3040
	21st to end	Night	2 7% 3 11% 8% 7% 9% 7% 12% 14% 20%	3106
December	1st to 10th	Night	1 5% 4 12% 9% 7% 9% 8% 10% 11% 23%	3410
	11th to 20th	Night	5% 3 10% 9% 8% 8% 7% 9% 11% 30%	4230
	21st to end	Night	1 6% 4 10% 7% 8% 9% 7% 11% 12% 26%	6270

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	37% 11% 12% 20% 16% 3	1551
	11th to 20th	Day	44% 14% 10% 16% 10% 6%	1580
	21st to end	Day	32% 20% 19% 17% 10% 2	2094
February	1st to 10th	Day	37% 12% 11% 17% 17% 6%	1330
	11th to 20th	Day	37% 15% 15% 15% 12% 5%	1446
	21st to end	Day	45% 12% 11% 16% 11% 4	1413
March	1st to 10th	Day	39% 17% 11% 17% 16% 1	2922
	11th to 20th	Day	36% 17% 18% 15% 11% 3	3467
	21st to end	Day	29% 20% 22% 20% 7% 3	3988
April	1st to 10th	Day	44% 16% 16% 16% 6% 1	2418
	11th to 20th	Day	44% 14% 16% 17% 8% 1	2550
	21st to end	Day	39% 17% 21% 18% 6%	2739
May	1st to 10th	Day	36% 16% 18% 22% 8% 1	4928
	11th to 20th	Day	39% 16% 17% 20% 7% 1	5043
	21st to end	Day	40% 16% 18% 18% 8%	5880
June	1st to 10th	Day	48% 14% 18% 13% 7%	3420
	11th to 20th	Day	57% 13% 15% 12% 4	3420
	21st to end	Day	52% 15% 17% 14% 2	3420
July	1st to 10th	Day	52% 14% 17% 13% 4	3229
	11th to 20th	Day	56% 17% 17% 8% 2	2967
	21st to end	Day	50% 16% 20% 11% 2	3086
August	1st to 10th	Day	45% 17% 20% 15% 3	2721
	11th to 20th	Day	51% 15% 19% 13% 2	2619
	21st to end	Day	58% 15% 16% 10% 1	2693
September	1st to 10th	Day	52% 14% 14% 16% 3	2278
	11th to 20th	Day	42% 17% 18% 19% 3	2156
	21st to end	Day	49% 15% 16% 16% 4	1898
October	1st to 10th	Day	49% 15% 16% 14% 5%	1800
	11th to 20th	Day	49% 15% 18% 12% 6%	1581
	21st to end	Day	51% 13% 14% 14% 7% 1	1584
November	1st to 10th	Day	49% 12% 15% 15% 7% 2	1264
	11th to 20th	Day	59% 11% 9% 14% 7% 1	1140
	21st to end	Day	45% 15% 14% 15% 10% 1	1065
December	1st to 10th	Day	50% 14% 14% 16% 5% 1	760
	11th to 20th	Day	37% 14% 10% 17% 20% 2	964
	21st to end	Day	33% 20% 14% 18% 13% 3	1386
January	1st to 10th	Night	35% 14% 13% 24% 12% 3	5422
	11th to 20th	Night	41% 14% 12% 15% 11% 7%	5380
	21st to end	Night	34% 22% 14% 18% 11% 2	5566
February	1st to 10th	Night	41% 11% 12% 17% 14% 5%	2850
	11th to 20th	Night	39% 14% 14% 16% 13% 4	2630
	21st to end	Night	45% 10% 13% 18% 10% 4	2041
March	1st to 10th	Night	44% 13% 10% 17% 14% 1	3942
	11th to 20th	Night	42% 17% 13% 14% 12% 2	3491
	21st to end	Night	30% 21% 22% 19% 6% 2	3648
April	1st to 10th	Night	42% 14% 18% 18% 8% 1	1762
	11th to 20th	Night	43% 13% 17% 17% 8% 1	1579
	21st to end	Night	40% 17% 19% 17% 8%	1439
May	1st to 10th	Night	33% 17% 18% 21% 9% 1	2036
	11th to 20th	Night	34% 16% 17% 24% 9%	1853
	21st to end	Night	46% 16% 15% 17% 7%	1695
June	1st to 10th	Night	45% 14% 19% 18% 4	760
	11th to 20th	Night	53% 13% 16% 14% 3	760
	21st to end	Night	50% 17% 19% 13% 1	760
July	1st to 10th	Night	47% 14% 18% 16% 5%	784
	11th to 20th	Night	56% 16% 17% 11% 1	870
	21st to end	Night	48% 15% 24% 11% 2	991
August	1st to 10th	Night	45% 16% 21% 16% 2	1193
	11th to 20th	Night	50% 13% 21% 15% 1	1281
	21st to end	Night	55% 16% 18% 11% 1	1660
September	1st to 10th	Night	48% 15% 18% 16% 3	1682
	11th to 20th	Night	41% 15% 19% 19% 5%	1804
	21st to end	Night	50% 14% 16% 14% 5% 1	2061
October	1st to 10th	Night	50% 13% 14% 16% 6% 1	2160
	11th to 20th	Night	55% 15% 14% 10% 5% 1	2377
	21st to end	Night	54% 13% 14% 13% 5% 2	2772
November	1st to 10th	Night	51% 15% 12% 14% 7% 1	2813
	11th to 20th	Night	56% 12% 11% 14% 7% 1	3040
	21st to end	Night	43% 16% 15% 18% 8% 1	3106
December	1st to 10th	Night	46% 16% 14% 17% 7% 1	3410
	11th to 20th	Night	40% 13% 12% 17% 15% 2	4227
	21st to end	Night	36% 21% 12% 14% 13% 3	6270

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	1 11% 16% 33% 28% 11%	90
	11th to 20th	Day	2 6% 23% 30% 29% 10%	90
	21st to end	Day	6% 10% 29% 30% 17% 8%	242
February	1st to 10th	Day	4 8% 25% 34% 23% 7%	370
	11th to 20th	Day	1 13% 31% 33% 13% 9%	365
	21st to end	Day	3 9% 33% 35% 13% 7%	307
March	1st to 10th	Day	2 10% 27% 27% 22% 12%	370
	11th to 20th	Day	2 12% 34% 26% 20% 6%	370
	21st to end	Day	2 10% 32% 28% 22% 6%	454
April	1st to 10th	Day	2 11% 30% 32% 21% 3	598
	11th to 20th	Day	5% 11% 22% 33% 25% 5%	640
	21st to end	Day	5% 10% 23% 33% 24% 5%	650
May	1st to 10th	Day	8% 14% 32% 29% 15% 3	653
	11th to 20th	Day	8% 12% 25% 29% 18% 7%	675
	21st to end	Day	10% 12% 27% 32% 15% 4	744
June	1st to 10th	Day	13% 9% 26% 29% 19% 5%	870
	11th to 20th	Day	16% 9% 24% 27% 19% 5%	870
	21st to end	Day	13% 9% 20% 27% 24% 7%	870
July	1st to 10th	Day	14% 6% 22% 28% 24% 6%	786
	11th to 20th	Day	18% 11% 21% 27% 19% 4	618
	21st to end	Day	14% 10% 23% 28% 20% 5%	684
August	1st to 10th	Day	13% 9% 27% 24% 21% 5%	626
	11th to 20th	Day	17% 17% 26% 22% 14% 4	615
	21st to end	Day	16% 13% 26% 27% 16% 2	693
September	1st to 10th	Day	16% 16% 23% 23% 16% 5%	568
	11th to 20th	Day	13% 15% 24% 25% 18% 5%	448
	21st to end	Day	16% 20% 28% 21% 8% 7%	360
October	1st to 10th	Day	12% 19% 32% 19% 12% 5%	360
	11th to 20th	Day	10% 16% 30% 23% 15% 6%	360
	21st to end	Day	7% 10% 29% 33% 18% 4	396
November	1st to 10th	Day	8% 10% 27% 34% 15% 6%	251
	11th to 20th	Day	4 12% 17% 34% 23% 9%	180
	21st to end	Day	3 11% 31% 23% 20% 12%	149
December	1st to 10th	Day	3 10% 21% 31% 22% 12%	90
	11th to 20th	Day	4 6% 17% 40% 28% 6%	90
	21st to end	Day	4 14% 18% 26% 24% 13%	99
January	1st to 10th	Night	2 7% 25% 35% 25% 6%	880
	11th to 20th	Night	2 8% 32% 32% 21% 4	850
	21st to end	Night	4 8% 32% 31% 18% 6%	935
February	1st to 10th	Night	2 8% 26% 38% 22% 3	850
	11th to 20th	Night	2 10% 33% 32% 17% 5%	834
	21st to end	Night	2 8% 28% 39% 19% 5%	703
March	1st to 10th	Night	2 6% 29% 31% 24% 8%	820
	11th to 20th	Night	5% 9% 24% 32% 21% 10%	581
	21st to end	Night	3 7% 24% 31% 27% 8%	627
April	1st to 10th	Night	4 7% 21% 34% 29% 6%	570
	11th to 20th	Night	5% 5% 22% 31% 30% 7%	563
	21st to end	Night	6% 5% 20% 31% 31% 7%	570
May	1st to 10th	Night	5% 9% 27% 30% 25% 4	464
	11th to 20th	Night	11% 9% 24% 28% 26% 2	358
	21st to end	Night	9% 5% 19% 30% 29% 7%	206
June	1st to 10th	Night	15% 3 24% 29% 26% 3	190
	11th to 20th	Night	17% 5% 17% 32% 27% 1	190
	21st to end	Night	16% 5% 17% 33% 28% 2	190
July	1st to 10th	Night	18% 2 20% 31% 28% 1	183
	11th to 20th	Night	20% 7% 17% 25% 26% 5%	174
	21st to end	Night	17% 5% 15% 31% 25% 6%	261
August	1st to 10th	Night	12% 7% 20% 31% 24% 5%	483
	11th to 20th	Night	16% 8% 22% 27% 20% 6%	534
	21st to end	Night	18% 7% 18% 31% 21% 4	594
September	1st to 10th	Night	19% 11% 22% 27% 17% 4	540
	11th to 20th	Night	11% 8% 23% 32% 22% 4	540
	21st to end	Night	16% 16% 23% 26% 14% 5%	621
October	1st to 10th	Night	12% 14% 28% 28% 14% 4	720
	11th to 20th	Night	12% 10% 24% 30% 19% 6%	780
	21st to end	Night	6% 7% 27% 35% 19% 5%	891
November	1st to 10th	Night	5% 8% 27% 35% 19% 7%	830
	11th to 20th	Night	4 8% 26% 32% 22% 7%	850
	21st to end	Night	5% 12% 29% 26% 20% 9%	850
December	1st to 10th	Night	3 10% 26% 33% 22% 6%	1030
	11th to 20th	Night	5% 7% 24% 35% 22% 8%	1040
	21st to end	Night	4 7% 28% 30% 20% 11%	1144

Page generated at 2024-07-05 07:05:38. Version ac07

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