Canyonlands National Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Canyonlands National Park clear sky chart from 2005-11-06 to 2024-03-08.

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	3 4 2 4 5% 3 5% 5% 6% 8% 56%	78646
	Night	3 4 2 4 5% 3 5% 5% 6% 9% 53%	80953
Transparency	Day	23% 5% 10% 21% 23% 17%	78371
	Night	24% 5% 10% 23% 23% 15%	80749
Seeing	Day	7% 11% 24% 32% 21% 6%	13912
	Night	5% 6% 18% 40% 27% 4	24454

By Month

Percentage Cloud Cover SW (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 7% 3 7% 6% 4 7% 9% 8% 11% 35%	2858
	11th to 20th	Day	3 5% 2 6% 7% 5% 6% 6% 8% 9% 42%	2860
	21st to end	Day	4 7% 3 6% 6% 4 7% 6% 8% 10% 40%	3146
February	1st to 10th	Day	2 5% 2 7% 9% 4 5% 6% 6% 11% 42%	1710
	11th to 20th	Day	4 5% 3 5% 7% 4 5% 5% 7% 10% 45%	1665
	21st to end	Day	3 6% 2 5% 6% 3 6% 6% 7% 10% 47%	1633
March	1st to 10th	Day	3 7% 3 5% 5% 3 6% 6% 6% 8% 48%	2058
	11th to 20th	Day	3 6% 2 4 6% 4 5% 5% 7% 9% 48%	1980
	21st to end	Day	3 4 3 6% 5% 3 5% 4 7% 9% 51%	2178
April	1st to 10th	Day	3 4 2 3 5% 3 6% 4 6% 8% 57%	2060
	11th to 20th	Day	2 4 2 4 5% 3 5% 5% 6% 9% 56%	2131
	21st to end	Day	2 3 1 3 4 3 5% 5% 6% 9% 59%	2283
May	1st to 10th	Day	3 4 2 3 4 3 5% 7% 7% 10% 54%	2340
	11th to 20th	Day	2 3 1 3 3 3 4 4 6% 8% 62%	2301
	21st to end	Day	2 3 2 3 3 2 5% 4 6% 9% 61%	2530
June	1st to 10th	Day	2 2 1 1 2 1 3 3 6% 7% 71%	2420
	11th to 20th	Day	2 2 1 2 2 1 3 3 4 6% 75%	2520
	21st to end	Day	1 1 1 2 2 2 3 4 4 7% 73%	2341
July	1st to 10th	Day	2 2 1 4 3 3 4 4 6% 8% 62%	2340
	11th to 20th	Day	2 2 2 2 4 3 5% 6% 8% 11% 55%	2340
	21st to end	Day	2 3 2 5% 5% 4 5% 7% 9% 12% 46%	2545
August	1st to 10th	Day	3 3 2 5% 5% 4 5% 6% 7% 8% 53%	2328
	11th to 20th	Day	1 2 2 4 4 3 4 6% 6% 9% 58%	2299
	21st to end	Day	2 2 1 3 4 2 5% 6% 6% 9% 59%	2427
September	1st to 10th	Day	3 2 1 3 3 2 4 4 5% 7% 65%	2149
	11th to 20th	Day	2 2 1 3 3 2 3 5% 4 7% 69%	1980
	21st to end	Day	3 2 1 2 3 2 2 3 3 6% 74%	1980
October	1st to 10th	Day	4 3 2 3 3 2 4 4 4 6% 65%	1818
	11th to 20th	Day	3 3 1 3 2 1 2 2 3 5% 74%	1800
	21st to end	Day	4 3 1 3 3 2 3 3 3 5% 70%	1980
November	1st to 10th	Day	3 3 2 2 3 1 3 2 4 6% 72%	1859
	11th to 20th	Day	2 3 2 3 3 2 3 3 4 6% 70%	1720
	21st to end	Day	4 3 2 5% 4 2 4 4 5% 7% 61%	1530
December	1st to 10th	Day	3 8% 3 5% 4 4 4 5% 6% 8% 51%	1520
	11th to 20th	Day	4 6% 3 7% 9% 5% 9% 7% 7% 10% 33%	1926
	21st to end	Day	4 8% 3 7% 7% 4 7% 6% 7% 10% 38%	3091
January	1st to 10th	Night	3 9% 5% 7% 6% 4 6% 6% 7% 12% 35%	4097
	11th to 20th	Night	2 5% 2 5% 7% 5% 8% 6% 7% 9% 46%	4110
	21st to end	Night	5% 9% 4 7% 7% 4 5% 6% 7% 11% 35%	4521
February	1st to 10th	Night	2 5% 2 6% 6% 4 6% 6% 7% 11% 47%	2470
	11th to 20th	Night	3 6% 3 6% 7% 4 5% 6% 7% 10% 43%	2402
	21st to end	Night	3 6% 3 5% 6% 3 5% 7% 8% 9% 46%	1815
March	1st to 10th	Night	3 5% 3 5% 5% 3 5% 6% 7% 10% 49%	2062
	11th to 20th	Night	3 4 2 4 4 3 6% 6% 5% 8% 55%	1980
	21st to end	Night	3 4 2 6% 5% 4 6% 6% 6% 8% 50%	2178
April	1st to 10th	Night	4 4 2 5% 5% 3 5% 5% 6% 9% 53%	1898
	11th to 20th	Night	3 4 2 6% 5% 3 3 5% 6% 9% 54%	1777
	21st to end	Night	3 3 2 3 3 3 4 6% 7% 8% 57%	1674
May	1st to 10th	Night	3 4 2 3 4 3 6% 5% 6% 9% 56%	1620
	11th to 20th	Night	2 3 2 4 4 3 5% 5% 5% 7% 59%	1594
	21st to end	Night	2 3 2 4 3 3 3 5% 5% 8% 63%	1746
June	1st to 10th	Night	2 2 1 2 3 2 3 4 5% 7% 69%	1529
	11th to 20th	Night	2 3 1 3 3 2 4 3 5% 7% 68%	1440
	21st to end	Night	1 2 1 3 3 2 3 4 4 7% 69%	1607
July	1st to 10th	Night	1 1 1 3 4 3 6% 5% 8% 10% 58%	1620
	11th to 20th	Night	2 3 2 5% 6% 3 6% 6% 8% 10% 49%	1620
	21st to end	Night	2 3 2 4 6% 5% 7% 7% 9% 12% 43%	1773
August	1st to 10th	Night	2 3 1 5% 5% 3 5% 6% 7% 10% 52%	1611
	11th to 20th	Night	2 3 2 3 5% 3 4 6% 7% 10% 55%	1602
	21st to end	Night	2 2 1 4 4 3 5% 6% 6% 9% 58%	1927
September	1st to 10th	Night	3 3 1 3 3 2 4 4 5% 6% 65%	1808
	11th to 20th	Night	2 2 1 3 4 2 3 4 4 8% 66%	1980
	21st to end	Night	4 2 1 2 3 2 3 3 3 5% 73%	1980
October	1st to 10th	Night	4 2 1 4 3 2 4 5% 5% 6% 64%	2141
	11th to 20th	Night	3 2 1 2 2 2 2 2 3 6% 74%	2160
	21st to end	Night	4 4 1 3 3 1 2 3 4 6% 68%	2376
November	1st to 10th	Night	2 3 1 2 3 2 4 4 4 6% 69%	2220
	11th to 20th	Night	3 3 1 3 3 2 3 4 4 7% 68%	2455
	21st to end	Night	4 4 2 3 3 2 4 4 5% 8% 60%	2626
December	1st to 10th	Night	4 6% 2 5% 4 3 4 4 5% 9% 53%	2660
	11th to 20th	Night	4 6% 3 6% 6% 4 5% 7% 9% 15% 36%	3271
	21st to end	Night	5% 8% 4 6% 5% 4 6% 7% 7% 13% 35%	4603

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	34% 8% 16% 32% 10% 1	2859
	11th to 20th	Day	31% 6% 18% 36% 6% 3	2860
	21st to end	Day	33% 5% 16% 29% 14% 2	3146
February	1st to 10th	Day	31% 6% 17% 24% 18% 4	1710
	11th to 20th	Day	30% 5% 12% 25% 23% 5%	1674
	21st to end	Day	28% 6% 8% 25% 27% 6%	1633
March	1st to 10th	Day	29% 5% 7% 26% 26% 6%	2058
	11th to 20th	Day	28% 6% 9% 26% 22% 8%	1980
	21st to end	Day	27% 5% 10% 26% 25% 6%	2178
April	1st to 10th	Day	24% 4 7% 21% 28% 15%	2060
	11th to 20th	Day	23% 4 8% 24% 26% 15%	2134
	21st to end	Day	19% 5% 8% 22% 34% 12%	2283
May	1st to 10th	Day	22% 6% 8% 18% 31% 15%	2340
	11th to 20th	Day	18% 5% 9% 19% 31% 18%	2304
	21st to end	Day	19% 5% 8% 17% 29% 22%	2530
June	1st to 10th	Day	12% 3 6% 13% 32% 35%	2420
	11th to 20th	Day	11% 3 4 9% 21% 51%	2520
	21st to end	Day	11% 3 5% 8% 21% 52%	2341
July	1st to 10th	Day	18% 6% 8% 11% 14% 42%	2276
	11th to 20th	Day	20% 7% 12% 17% 19% 26%	2271
	21st to end	Day	27% 9% 14% 17% 16% 16%	2404
August	1st to 10th	Day	26% 7% 11% 16% 16% 24%	2313
	11th to 20th	Day	20% 6% 10% 16% 18% 30%	2299
	21st to end	Day	20% 6% 8% 16% 23% 27%	2427
September	1st to 10th	Day	19% 4 8% 12% 21% 36%	2149
	11th to 20th	Day	15% 6% 8% 17% 21% 33%	1980
	21st to end	Day	14% 4 4 13% 36% 29%	1980
October	1st to 10th	Day	20% 5% 8% 22% 26% 19%	1818
	11th to 20th	Day	15% 3 5% 19% 37% 21%	1800
	21st to end	Day	19% 3 6% 29% 33% 10%	1980
November	1st to 10th	Day	14% 3 9% 29% 34% 11%	1859
	11th to 20th	Day	17% 4 8% 34% 34% 3	1720
	21st to end	Day	22% 5% 11% 32% 26% 5%	1530
December	1st to 10th	Day	29% 7% 16% 29% 15% 4	1520
	11th to 20th	Day	36% 9% 15% 30% 9%	1924
	21st to end	Day	35% 7% 14% 17% 23% 4	3091
January	1st to 10th	Night	34% 6% 14% 32% 13%	4097
	11th to 20th	Night	27% 6% 20% 35% 12% 1	4110
	21st to end	Night	35% 6% 14% 29% 14% 2	4521
February	1st to 10th	Night	28% 5% 15% 27% 20% 5%	2470
	11th to 20th	Night	29% 5% 10% 25% 24% 6%	2403
	21st to end	Night	29% 5% 9% 25% 26% 6%	1815
March	1st to 10th	Night	27% 6% 8% 24% 29% 6%	2062
	11th to 20th	Night	24% 4 7% 28% 27% 10%	1980
	21st to end	Night	29% 6% 11% 25% 25% 5%	2178
April	1st to 10th	Night	27% 4 8% 19% 26% 15%	1898
	11th to 20th	Night	26% 4 7% 18% 28% 16%	1777
	21st to end	Night	21% 6% 8% 19% 34% 12%	1674
May	1st to 10th	Night	24% 5% 10% 16% 30% 16%	1620
	11th to 20th	Night	22% 6% 7% 19% 30% 16%	1595
	21st to end	Night	18% 4 8% 19% 32% 20%	1746
June	1st to 10th	Night	14% 4 4 12% 32% 34%	1529
	11th to 20th	Night	16% 3 6% 9% 16% 49%	1440
	21st to end	Night	13% 4 4 9% 20% 50%	1607
July	1st to 10th	Night	18% 6% 10% 13% 13% 41%	1575
	11th to 20th	Night	23% 7% 11% 17% 17% 25%	1566
	21st to end	Night	29% 8% 14% 21% 13% 15%	1674
August	1st to 10th	Night	21% 7% 11% 19% 19% 23%	1602
	11th to 20th	Night	21% 5% 9% 19% 15% 31%	1602
	21st to end	Night	20% 6% 10% 14% 22% 29%	1927
September	1st to 10th	Night	18% 5% 7% 13% 18% 39%	1808
	11th to 20th	Night	16% 5% 9% 17% 19% 33%	1980
	21st to end	Night	15% 3 5% 13% 31% 33%	1980
October	1st to 10th	Night	19% 5% 7% 21% 25% 23%	2141
	11th to 20th	Night	13% 2 6% 15% 38% 26%	2160
	21st to end	Night	19% 3 6% 24% 35% 14%	2376
November	1st to 10th	Night	17% 4 8% 21% 35% 15%	2220
	11th to 20th	Night	18% 3 8% 29% 38% 5%	2455
	21st to end	Night	23% 4 8% 23% 34% 8%	2626
December	1st to 10th	Night	27% 4 13% 31% 20% 5%	2660
	11th to 20th	Night	31% 6% 15% 33% 13%	3272
	21st to end	Night	33% 7% 14% 21% 21% 4	4603

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	10% 10% 22% 35% 17% 6%	270
	11th to 20th	Day	9% 8% 22% 37% 21% 3	270
	21st to end	Day	4 7% 19% 41% 25% 3	297
February	1st to 10th	Day	5% 9% 33% 37% 14% 3	270
	11th to 20th	Day	13% 7% 30% 33% 14% 3	270
	21st to end	Day	12% 18% 25% 31% 12% 1	377
March	1st to 10th	Day	10% 17% 29% 28% 16% 1	449
	11th to 20th	Day	9% 16% 28% 29% 13% 5%	420
	21st to end	Day	12% 23% 31% 25% 8% 1	462
April	1st to 10th	Day	8% 19% 29% 27% 13% 4	420
	11th to 20th	Day	13% 20% 32% 22% 10% 2	412
	21st to end	Day	10% 21% 31% 24% 13% 2	420
May	1st to 10th	Day	9% 17% 36% 26% 12% 1	423
	11th to 20th	Day	5% 14% 32% 27% 17% 5%	448
	21st to end	Day	7% 18% 29% 26% 15% 5%	485
June	1st to 10th	Day	4 10% 28% 34% 19% 6%	530
	11th to 20th	Day	3 11% 25% 34% 21% 5%	630
	21st to end	Day	3 10% 33% 33% 18% 4	451
July	1st to 10th	Day	3 4 21% 38% 27% 7%	446
	11th to 20th	Day	3 2 17% 32% 34% 12%	444
	21st to end	Day	3 1 11% 37% 37% 12%	487
August	1st to 10th	Day	6% 2 19% 40% 26% 8%	447
	11th to 20th	Day	3 5% 18% 35% 28% 11%	437
	21st to end	Day	4 3 20% 33% 32% 8%	495
September	1st to 10th	Day	3 5% 20% 30% 29% 12%	450
	11th to 20th	Day	3 11% 25% 30% 23% 8%	450
	21st to end	Day	5% 13% 21% 27% 25% 9%	450
October	1st to 10th	Day	10% 10% 19% 24% 27% 9%	288
	11th to 20th	Day	10% 11% 14% 27% 29% 8%	270
	21st to end	Day	7% 13% 18% 35% 25% 2	297
November	1st to 10th	Day	5% 16% 20% 30% 24% 4	270
	11th to 20th	Day	4 7% 24% 38% 20% 7%	270
	21st to end	Day	8% 5% 26% 33% 24% 4	270
December	1st to 10th	Day	6% 13% 22% 34% 22% 3	270
	11th to 20th	Day	6% 7% 22% 37% 24% 4	270
	21st to end	Day	14% 8% 22% 39% 15% 2	297
January	1st to 10th	Night	7% 6% 13% 41% 26% 6%	760
	11th to 20th	Night	6% 4 16% 42% 28% 3	760
	21st to end	Night	7% 4 16% 48% 22% 4	836
February	1st to 10th	Night	6% 5% 22% 44% 20% 4	760
	11th to 20th	Night	5% 7% 24% 44% 18% 2	744
	21st to end	Night	7% 8% 25% 44% 15% 1	628
March	1st to 10th	Night	5% 11% 23% 40% 19% 2	750
	11th to 20th	Night	6% 5% 21% 39% 26% 3	720
	21st to end	Night	5% 11% 25% 39% 17% 2	792
April	1st to 10th	Night	6% 11% 31% 36% 15% 1	638
	11th to 20th	Night	7% 12% 29% 35% 16% 1	533
	21st to end	Night	6% 13% 27% 30% 21% 3	540
May	1st to 10th	Night	5% 8% 26% 41% 17% 2	540
	11th to 20th	Night	4 5% 20% 42% 24% 5%	531
	21st to end	Night	4 11% 23% 35% 23% 4	584
June	1st to 10th	Night	3 5% 18% 41% 30% 2	540
	11th to 20th	Night	3 6% 23% 41% 25% 3	540
	21st to end	Night	1 2 18% 46% 28% 4	540
July	1st to 10th	Night	2 14% 33% 45% 6%	525
	11th to 20th	Night	3 1 10% 33% 47% 6%	522
	21st to end	Night	3 2 5% 32% 52% 7%	591
August	1st to 10th	Night	4 1 9% 36% 43% 6%	537
	11th to 20th	Night	3 2 12% 40% 37% 7%	534
	21st to end	Night	4 1 10% 38% 38% 8%	594
September	1st to 10th	Night	6% 2 9% 39% 38% 6%	548
	11th to 20th	Night	3 3 13% 38% 34% 10%	720
	21st to end	Night	5% 4 14% 35% 33% 8%	720
October	1st to 10th	Night	6% 5% 15% 43% 26% 4	720
	11th to 20th	Night	3 4 17% 42% 27% 7%	720
	21st to end	Night	7% 5% 18% 33% 31% 6%	792
November	1st to 10th	Night	4 5% 19% 37% 29% 5%	740
	11th to 20th	Night	5% 5% 17% 42% 27% 5%	760
	21st to end	Night	8% 6% 17% 36% 27% 6%	916
December	1st to 10th	Night	8% 5% 14% 49% 21% 4	950
	11th to 20th	Night	8% 6% 19% 40% 25% 3	950
	21st to end	Night	11% 7% 15% 43% 21% 3	879

Page generated at 2024-03-05 05:24:05. Version ac07

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