Carmacks
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Carmacks clear sky chart from 2005-11-06 to 2024-10-25.

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% 10% 4 11% 8% 7% 7% 5% 7% 8% 25%	103092
	Night	5% 11% 5% 13% 9% 7% 7% 6% 7% 8% 22%	95752
Transparency	Day	54% 3 16% 20% 7%	102777
	Night	57% 3 13% 19% 7% 1	95714
Seeing	Day	15% 7% 21% 29% 21% 7%	17192
	Night	12% 6% 17% 33% 27% 7%	23039

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 9% 5% 21% 11% 13% 12% 5% 9% 5% 8%	1261
	11th to 20th	Day	2 13% 6% 16% 13% 10% 8% 4 5% 11% 12%	1565
	21st to end	Day	2 11% 6% 16% 10% 8% 9% 6% 7% 9% 16%	2001
February	1st to 10th	Day	1 10% 6% 13% 9% 8% 8% 6% 9% 9% 19%	1308
	11th to 20th	Day	4 11% 5% 14% 10% 9% 7% 6% 8% 9% 18%	1419
	21st to end	Day	1 10% 6% 13% 11% 9% 8% 7% 6% 8% 21%	1387
March	1st to 10th	Day	1 8% 4 17% 12% 9% 8% 5% 6% 6% 24%	2997
	11th to 20th	Day	2 13% 5% 15% 8% 7% 6% 4 6% 8% 25%	3344
	21st to end	Day	1 8% 5% 14% 7% 6% 6% 4 6% 9% 34%	4088
April	1st to 10th	Day	3 13% 5% 13% 7% 6% 6% 6% 6% 9% 26%	2356
	11th to 20th	Day	4 13% 4 11% 7% 6% 6% 5% 6% 7% 31%	2624
	21st to end	Day	5% 11% 4 10% 8% 7% 6% 5% 7% 7% 30%	2712
May	1st to 10th	Day	6% 10% 4 10% 7% 6% 5% 4 6% 8% 34%	5060
	11th to 20th	Day	4 7% 3 8% 7% 7% 8% 7% 9% 10% 30%	5013
	21st to end	Day	7% 9% 4 10% 7% 7% 7% 5% 8% 9% 28%	6163
June	1st to 10th	Day	9% 9% 4 11% 9% 7% 8% 5% 7% 7% 26%	3420
	11th to 20th	Day	10% 11% 5% 11% 8% 7% 6% 5% 7% 8% 23%	3420
	21st to end	Day	12% 8% 3 10% 8% 7% 8% 6% 8% 9% 22%	3420
July	1st to 10th	Day	12% 9% 4 11% 8% 8% 8% 6% 8% 7% 20%	5700
	11th to 20th	Day	10% 8% 4 10% 7% 8% 7% 6% 7% 9% 24%	5579
	21st to end	Day	12% 8% 4 10% 7% 6% 7% 5% 8% 9% 25%	5679
August	1st to 10th	Day	8% 7% 3 8% 5% 5% 6% 4 6% 8% 39%	4990
	11th to 20th	Day	16% 9% 3 8% 6% 6% 5% 5% 7% 9% 27%	4528
	21st to end	Day	14% 10% 4 9% 7% 7% 7% 5% 7% 9% 20%	4873
September	1st to 10th	Day	12% 11% 3 11% 7% 6% 7% 5% 6% 9% 24%	2365
	11th to 20th	Day	10% 8% 3 8% 7% 7% 6% 5% 7% 8% 31%	2280
	21st to end	Day	13% 10% 4 9% 6% 7% 6% 5% 6% 8% 27%	2013
October	1st to 10th	Day	10% 12% 4 10% 7% 7% 6% 5% 8% 7% 24%	1900
	11th to 20th	Day	8% 15% 5% 11% 7% 6% 7% 5% 6% 7% 22%	1649
	21st to end	Day	7% 13% 6% 12% 9% 6% 6% 4 7% 6% 22%	1601
November	1st to 10th	Day	4 16% 8% 15% 9% 7% 8% 5% 6% 6% 16%	1226
	11th to 20th	Day	4 17% 8% 14% 11% 9% 8% 5% 7% 5% 13%	1140
	21st to end	Day	4 13% 7% 15% 10% 8% 8% 9% 7% 6% 15%	903
December	1st to 10th	Day	4 10% 6% 21% 12% 8% 7% 6% 10% 8% 9%	760
	11th to 20th	Day	3 12% 5% 13% 10% 6% 9% 9% 8% 11% 12%	962
	21st to end	Day	3 13% 6% 15% 10% 7% 7% 5% 9% 9% 16%	1386
January	1st to 10th	Night	3 11% 5% 17% 13% 13% 9% 7% 7% 5% 11%	5686
	11th to 20th	Night	3 15% 7% 16% 9% 7% 6% 4 8% 12% 14%	5361
	21st to end	Night	4 13% 6% 18% 11% 9% 8% 7% 7% 7% 13%	5654
February	1st to 10th	Night	2 10% 6% 14% 11% 8% 7% 6% 7% 9% 21%	2869
	11th to 20th	Night	2 10% 4 14% 9% 8% 7% 6% 8% 9% 23%	2648
	21st to end	Night	1 8% 4 11% 8% 8% 8% 6% 7% 8% 31%	2065
March	1st to 10th	Night	1 7% 3 15% 11% 8% 5% 5% 8% 8% 28%	3867
	11th to 20th	Night	3 14% 5% 12% 8% 7% 7% 5% 7% 7% 25%	3616
	21st to end	Night	2 10% 5% 14% 6% 7% 7% 4 7% 7% 31%	3552
April	1st to 10th	Night	2 11% 4 12% 8% 5% 5% 5% 7% 8% 32%	1821
	11th to 20th	Night	3 9% 4 12% 7% 7% 7% 6% 8% 6% 31%	1505
	21st to end	Night	4 8% 4 9% 6% 6% 6% 7% 8% 8% 34%	1466
May	1st to 10th	Night	3 6% 3 8% 6% 6% 7% 6% 10% 11% 35%	1900
	11th to 20th	Night	5% 6% 2 8% 6% 5% 7% 7% 9% 9% 35%	1882
	21st to end	Night	6% 7% 3 8% 5% 7% 7% 6% 9% 9% 32%	1410
June	1st to 10th	Night	8% 9% 3 7% 6% 6% 9% 5% 10% 9% 29%	760
	11th to 20th	Night	8% 8% 3 11% 8% 6% 7% 7% 9% 8% 25%	760
	21st to end	Night	11% 8% 5% 10% 8% 6% 8% 6% 11% 8% 20%	760
July	1st to 10th	Night	12% 11% 3 10% 7% 7% 6% 6% 7% 9% 22%	1260
	11th to 20th	Night	8% 6% 3 9% 5% 7% 6% 7% 10% 10% 30%	1379
	21st to end	Night	14% 10% 3 9% 6% 6% 6% 6% 8% 10% 23%	1872
August	1st to 10th	Night	7% 5% 3 7% 5% 5% 6% 5% 8% 7% 42%	1941
	11th to 20th	Night	16% 9% 3 6% 5% 4 6% 6% 7% 9% 29%	2310
	21st to end	Night	9% 9% 5% 11% 7% 7% 7% 5% 8% 8% 21%	2794
September	1st to 10th	Night	10% 9% 3 12% 7% 7% 7% 5% 7% 8% 24%	1814
	11th to 20th	Night	7% 6% 3 9% 7% 8% 7% 6% 7% 10% 33%	1900
	21st to end	Night	11% 12% 4 10% 6% 7% 7% 4 7% 7% 25%	2165
October	1st to 10th	Night	11% 11% 4 9% 6% 7% 6% 4 6% 8% 28%	2280
	11th to 20th	Night	9% 18% 5% 11% 6% 5% 5% 4 5% 7% 24%	2528
	21st to end	Night	5% 16% 6% 13% 8% 6% 6% 5% 7% 7% 20%	2860
November	1st to 10th	Night	7% 15% 6% 16% 9% 7% 7% 5% 5% 6% 18%	2851
	11th to 20th	Night	3 16% 8% 19% 11% 8% 7% 4 5% 5% 13%	3040
	21st to end	Night	5% 15% 6% 15% 10% 8% 8% 8% 7% 5% 13%	3256
December	1st to 10th	Night	5% 14% 6% 16% 12% 7% 7% 6% 8% 8% 11%	3420
	11th to 20th	Night	3 12% 6% 15% 11% 8% 9% 6% 9% 9% 12%	4230
	21st to end	Night	6% 14% 6% 13% 9% 8% 8% 6% 8% 7% 14%	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	72% 3 5% 12% 6% 2	1261
	11th to 20th	Day	67% 2 7% 9% 15%	1580
	21st to end	Day	61% 3 10% 16% 8% 1	2001
February	1st to 10th	Day	54% 4 9% 19% 13% 1	1308
	11th to 20th	Day	59% 4 12% 14% 10%	1426
	21st to end	Day	57% 4 14% 17% 8%	1387
March	1st to 10th	Day	60% 2 6% 25% 7%	2997
	11th to 20th	Day	56% 3 12% 18% 10%	3344
	21st to end	Day	47% 2 24% 17% 9% 1	4088
April	1st to 10th	Day	53% 4 16% 21% 7%	2356
	11th to 20th	Day	50% 3 14% 22% 10%	2624
	21st to end	Day	49% 3 14% 24% 9%	2712
May	1st to 10th	Day	47% 2 10% 31% 9%	5060
	11th to 20th	Day	46% 1 9% 31% 13%	5016
	21st to end	Day	51% 2 10% 25% 13%	6164
June	1st to 10th	Day	56% 2 11% 23% 7% 1	3420
	11th to 20th	Day	59% 2 11% 22% 5%	3420
	21st to end	Day	56% 3 16% 21% 3	3420
July	1st to 10th	Day	58% 2 20% 15% 4 1	5611
	11th to 20th	Day	54% 3 22% 18% 3	5480
	21st to end	Day	53% 2 23% 19% 2	5499
August	1st to 10th	Day	43% 3 22% 20% 10% 2	4971
	11th to 20th	Day	54% 3 19% 21% 3	4573
	21st to end	Day	58% 2 23% 17% 1	4872
September	1st to 10th	Day	57% 3 19% 18% 3	2365
	11th to 20th	Day	49% 3 23% 22% 2	2280
	21st to end	Day	55% 2 19% 21% 4	2013
October	1st to 10th	Day	56% 6% 17% 17% 3	1900
	11th to 20th	Day	58% 5% 20% 14% 3	1649
	21st to end	Day	59% 5% 17% 16% 3	1601
November	1st to 10th	Day	62% 5% 13% 17% 2	1226
	11th to 20th	Day	68% 4 13% 12% 3	1140
	21st to end	Day	62% 5% 13% 15% 5%	903
December	1st to 10th	Day	67% 7% 14% 9% 4	760
	11th to 20th	Day	59% 3 7% 15% 15% 1	964
	21st to end	Day	60% 3 10% 20% 7%	1386
January	1st to 10th	Night	70% 3 7% 12% 6% 1	5686
	11th to 20th	Night	61% 2 7% 13% 12% 5%	5408
	21st to end	Night	67% 4 7% 15% 5% 2	5654
February	1st to 10th	Night	55% 5% 8% 19% 12% 1	2869
	11th to 20th	Night	53% 5% 11% 21% 9% 1	2652
	21st to end	Night	48% 4 16% 20% 12%	2065
March	1st to 10th	Night	52% 1 8% 27% 12%	3867
	11th to 20th	Night	56% 2 10% 21% 9% 1	3618
	21st to end	Night	49% 2 20% 19% 8% 1	3552
April	1st to 10th	Night	49% 3 17% 22% 8% 1	1821
	11th to 20th	Night	48% 3 14% 26% 9% 1	1505
	21st to end	Night	44% 2 16% 28% 9%	1466
May	1st to 10th	Night	39% 2 12% 37% 10%	1900
	11th to 20th	Night	44% 2 11% 30% 14%	1882
	21st to end	Night	44% 1 11% 28% 14% 1	1410
June	1st to 10th	Night	47% 3 14% 28% 7% 1	760
	11th to 20th	Night	52% 5% 12% 25% 5% 1	760
	21st to end	Night	54% 4 16% 21% 5%	760
July	1st to 10th	Night	56% 3 20% 17% 3 1	1240
	11th to 20th	Night	43% 2 26% 23% 5%	1355
	21st to end	Night	55% 2 24% 17% 2	1813
August	1st to 10th	Night	37% 4 25% 21% 13% 1	1935
	11th to 20th	Night	50% 3 19% 26% 2	2331
	21st to end	Night	57% 2 18% 22% 1	2794
September	1st to 10th	Night	57% 3 19% 19% 2	1814
	11th to 20th	Night	46% 3 24% 23% 4	1900
	21st to end	Night	56% 3 17% 19% 5%	2165
October	1st to 10th	Night	54% 5% 16% 21% 4	2280
	11th to 20th	Night	60% 3 18% 16% 3	2528
	21st to end	Night	60% 6% 20% 12% 3	2860
November	1st to 10th	Night	64% 4 15% 14% 3	2851
	11th to 20th	Night	71% 3 10% 12% 3	3040
	21st to end	Night	66% 5% 11% 16% 3	3256
December	1st to 10th	Night	67% 5% 13% 12% 3	3420
	11th to 20th	Night	64% 4 9% 14% 7% 2	4227
	21st to end	Night	64% 4 6% 14% 9% 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	4 2 12% 29% 43% 9%	90
	11th to 20th	Day	9% 11% 38% 19% 23%	90
	21st to end	Day	8% 7% 19% 32% 22% 12%	175
February	1st to 10th	Day	7% 4 17% 38% 24% 11%	348
	11th to 20th	Day	9% 5% 17% 35% 21% 13%	365
	21st to end	Day	6% 7% 23% 38% 21% 5%	307
March	1st to 10th	Day	6% 9% 25% 27% 21% 12%	370
	11th to 20th	Day	7% 9% 27% 32% 17% 7%	370
	21st to end	Day	7% 8% 27% 29% 21% 8%	483
April	1st to 10th	Day	12% 10% 26% 28% 19% 5%	536
	11th to 20th	Day	12% 10% 23% 28% 21% 5%	640
	21st to end	Day	12% 10% 22% 32% 17% 8%	650
May	1st to 10th	Day	17% 13% 28% 26% 12% 4	653
	11th to 20th	Day	13% 10% 27% 28% 15% 7%	675
	21st to end	Day	14% 8% 27% 27% 19% 5%	915
June	1st to 10th	Day	15% 6% 19% 31% 24% 6%	870
	11th to 20th	Day	17% 6% 17% 31% 22% 7%	870
	21st to end	Day	16% 5% 16% 28% 25% 10%	870
July	1st to 10th	Day	14% 5% 17% 29% 26% 8%	856
	11th to 20th	Day	18% 6% 18% 28% 22% 8%	783
	21st to end	Day	19% 3 14% 29% 26% 8%	739
August	1st to 10th	Day	15% 4 23% 29% 20% 8%	676
	11th to 20th	Day	23% 7% 24% 26% 16% 4	665
	21st to end	Day	18% 6% 22% 31% 19% 4	748
September	1st to 10th	Day	21% 10% 20% 19% 20% 9%	566
	11th to 20th	Day	17% 7% 21% 26% 21% 8%	490
	21st to end	Day	23% 12% 22% 21% 14% 6%	425
October	1st to 10th	Day	18% 11% 28% 21% 15% 7%	390
	11th to 20th	Day	21% 11% 21% 23% 18% 8%	390
	21st to end	Day	15% 6% 16% 30% 24% 9%	392
November	1st to 10th	Day	17% 6% 21% 27% 23% 6%	180
	11th to 20th	Day	11% 4 12% 34% 28% 10%	180
	21st to end	Day	9% 6% 16% 35% 19% 14%	156
December	1st to 10th	Day	7% 4 14% 33% 30% 11%	90
	11th to 20th	Day	14% 1 16% 31% 24% 13%	90
	21st to end	Day	6% 7% 17% 23% 30% 16%	99
January	1st to 10th	Night	6% 5% 13% 35% 32% 9%	1040
	11th to 20th	Night	10% 5% 15% 41% 25% 5%	865
	21st to end	Night	10% 4 21% 37% 22% 6%	935
February	1st to 10th	Night	6% 4 15% 41% 28% 6%	850
	11th to 20th	Night	6% 7% 19% 39% 24% 6%	834
	21st to end	Night	6% 5% 19% 42% 24% 4	703
March	1st to 10th	Night	6% 7% 20% 33% 27% 6%	798
	11th to 20th	Night	6% 5% 23% 34% 26% 7%	656
	21st to end	Night	6% 6% 20% 30% 30% 7%	627
April	1st to 10th	Night	8% 5% 19% 32% 28% 7%	570
	11th to 20th	Night	7% 5% 19% 34% 29% 6%	563
	21st to end	Night	8% 7% 15% 29% 35% 7%	556
May	1st to 10th	Night	13% 10% 17% 28% 28% 4	380
	11th to 20th	Night	13% 9% 23% 29% 26% 1	374
	21st to end	Night	8% 5% 27% 27% 30% 3	209
June	1st to 10th	Night	13% 7% 19% 27% 28% 6%	190
	11th to 20th	Night	15% 6% 13% 29% 34% 3	190
	21st to end	Night	14% 7% 15% 23% 32% 8%	190
July	1st to 10th	Night	14% 2 15% 30% 37% 3	185
	11th to 20th	Night	17% 4 17% 23% 30% 9%	184
	21st to end	Night	17% 4 13% 24% 35% 6%	300
August	1st to 10th	Night	12% 5% 18% 29% 32% 5%	400
	11th to 20th	Night	20% 7% 17% 26% 24% 7%	564
	21st to end	Night	15% 4 15% 29% 31% 6%	627
September	1st to 10th	Night	18% 9% 16% 25% 25% 8%	570
	11th to 20th	Night	12% 7% 17% 33% 26% 5%	570
	21st to end	Night	19% 9% 16% 26% 22% 7%	716
October	1st to 10th	Night	19% 10% 18% 27% 21% 5%	760
	11th to 20th	Night	20% 7% 12% 30% 26% 5%	798
	21st to end	Night	14% 5% 14% 35% 25% 7%	916
November	1st to 10th	Night	15% 5% 13% 35% 24% 7%	830
	11th to 20th	Night	10% 3 17% 34% 30% 7%	850
	21st to end	Night	14% 5% 19% 30% 23% 8%	1015
December	1st to 10th	Night	13% 4 15% 37% 26% 7%	1040
	11th to 20th	Night	13% 3 15% 36% 26% 7%	1040
	21st to end	Night	9% 5% 12% 35% 28% 11%	1144

Page generated at 2024-10-22 16:21:03. Version ac07

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