Duette Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Duette Park clear sky chart from 2005-11-06 to 2024-12-09.

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	7% 6% 2 7% 6% 6% 6% 5% 7% 9% 39%	101179
	Night	8% 6% 2 7% 5% 5% 5% 5% 7% 9% 41%	98554
Transparency	Day	38% 9% 16% 19% 13% 4	104969
	Night	37% 9% 17% 20% 14% 4	102903
Seeing	Day	8% 4 16% 25% 25% 22%	15673
	Night	8% 4 17% 34% 28% 9%	25738

By Month

Percentage Cloud Cover SE (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	10% 7% 4 8% 5% 4 4 4 5% 8% 41%	2836
	11th to 20th	Day	20% 8% 3 7% 5% 3 4 3 5% 7% 35%	2840
	21st to end	Day	11% 6% 2 7% 5% 4 4 4 6% 8% 43%	3359
February	1st to 10th	Day	11% 5% 2 6% 4 4 4 4 7% 6% 46%	1900
	11th to 20th	Day	6% 5% 1 4 4 4 3 5% 6% 7% 55%	1848
	21st to end	Day	7% 4 2 5% 4 5% 4 4 6% 7% 51%	1652
March	1st to 10th	Day	7% 5% 2 8% 7% 6% 6% 5% 6% 9% 39%	3435
	11th to 20th	Day	5% 4 2 6% 4 4 4 4 6% 10% 51%	3480
	21st to end	Day	9% 4 2 4 4 4 4 3 6% 8% 52%	3815
April	1st to 10th	Day	6% 3 2 4 5% 5% 5% 5% 7% 10% 49%	2090
	11th to 20th	Day	8% 5% 2 6% 5% 5% 6% 4 7% 9% 43%	2066
	21st to end	Day	5% 4 2 5% 4 4 5% 5% 6% 9% 52%	2256
May	1st to 10th	Day	3 3 1 4 4 4 5% 4 5% 9% 57%	4038
	11th to 20th	Day	8% 5% 2 6% 5% 5% 5% 5% 7% 11% 41%	4081
	21st to end	Day	4 4 2 5% 5% 5% 4 4 6% 8% 52%	4476
June	1st to 10th	Day	11% 10% 3 9% 8% 7% 8% 5% 7% 9% 23%	2470
	11th to 20th	Day	7% 6% 3 9% 8% 8% 8% 6% 9% 9% 26%	2470
	21st to end	Day	8% 7% 4 9% 8% 8% 8% 7% 9% 9% 24%	2470
July	1st to 10th	Day	6% 6% 3 10% 8% 8% 7% 7% 9% 12% 25%	4120
	11th to 20th	Day	5% 5% 3 9% 8% 8% 7% 7% 10% 14% 24%	4120
	21st to end	Day	7% 6% 3 9% 8% 8% 8% 6% 9% 11% 24%	4466
August	1st to 10th	Day	6% 6% 3 11% 7% 7% 7% 6% 8% 12% 26%	4104
	11th to 20th	Day	4 5% 2 8% 7% 8% 8% 6% 8% 10% 34%	3677
	21st to end	Day	7% 5% 3 9% 8% 7% 7% 7% 10% 13% 24%	3828
September	1st to 10th	Day	6% 8% 3 10% 8% 9% 8% 6% 8% 12% 23%	2090
	11th to 20th	Day	8% 7% 3 10% 9% 9% 7% 6% 8% 10% 24%	2090
	21st to end	Day	8% 6% 3 10% 8% 7% 6% 5% 7% 9% 30%	2090
October	1st to 10th	Day	9% 7% 3 8% 6% 6% 6% 5% 6% 9% 36%	2090
	11th to 20th	Day	7% 5% 2 6% 4 5% 6% 4 6% 7% 47%	1924
	21st to end	Day	7% 5% 2 6% 3 5% 4 4 5% 10% 49%	2090
November	1st to 10th	Day	7% 4 2 5% 5% 5% 4 4 7% 8% 50%	1957
	11th to 20th	Day	7% 6% 2 6% 5% 4 5% 4 5% 7% 47%	2000
	21st to end	Day	7% 5% 2 5% 5% 4 5% 4 6% 8% 48%	1892
December	1st to 10th	Day	6% 5% 2 5% 4 5% 5% 4 7% 8% 48%	1782
	11th to 20th	Day	10% 7% 3 6% 5% 4 4 4 6% 8% 46%	2153
	21st to end	Day	11% 8% 3 9% 7% 6% 5% 4 5% 7% 34%	3124
January	1st to 10th	Night	11% 7% 3 8% 5% 5% 5% 4 6% 8% 37%	4109
	11th to 20th	Night	19% 11% 3 8% 4 4 4 4 5% 7% 31%	4120
	21st to end	Night	9% 6% 3 7% 5% 5% 5% 5% 7% 8% 39%	4280
February	1st to 10th	Night	9% 7% 2 6% 5% 5% 4 4 5% 8% 46%	2280
	11th to 20th	Night	9% 5% 2 4 4 4 5% 3 5% 7% 53%	2218
	21st to end	Night	6% 5% 2 6% 4 3 4 3 6% 9% 52%	1799
March	1st to 10th	Night	10% 8% 3 8% 5% 5% 4 4 5% 7% 39%	3418
	11th to 20th	Night	4 3 1 6% 3 4 4 4 8% 12% 50%	3480
	21st to end	Night	8% 5% 2 5% 4 3 4 3 5% 7% 53%	3817
April	1st to 10th	Night	5% 4 1 4 4 3 3 4 6% 10% 55%	2090
	11th to 20th	Night	5% 4 2 5% 3 4 4 4 7% 10% 50%	2063
	21st to end	Night	4 3 1 5% 4 4 4 4 5% 8% 56%	1920
May	1st to 10th	Night	4 4 2 5% 4 4 4 3 5% 7% 57%	2884
	11th to 20th	Night	7% 5% 2 5% 3 4 4 4 7% 9% 48%	2812
	21st to end	Night	4 4 1 5% 3 4 4 4 5% 8% 60%	3079
June	1st to 10th	Night	9% 6% 2 7% 4 5% 5% 5% 7% 10% 38%	1710
	11th to 20th	Night	5% 6% 3 7% 5% 5% 7% 6% 8% 12% 36%	1710
	21st to end	Night	5% 4 3 8% 6% 7% 6% 6% 10% 13% 32%	1710
July	1st to 10th	Night	7% 7% 3 11% 7% 7% 6% 6% 9% 11% 26%	2840
	11th to 20th	Night	4 5% 3 9% 8% 7% 8% 7% 10% 13% 26%	2840
	21st to end	Night	7% 9% 4 13% 9% 8% 8% 6% 8% 10% 18%	3087
August	1st to 10th	Night	5% 5% 3 8% 7% 6% 5% 6% 9% 14% 33%	2825
	11th to 20th	Night	3 4 2 7% 5% 6% 7% 6% 9% 14% 35%	3111
	21st to end	Night	6% 6% 2 8% 6% 7% 7% 7% 11% 13% 27%	3828
September	1st to 10th	Night	6% 7% 3 8% 6% 7% 7% 6% 9% 13% 29%	2090
	11th to 20th	Night	10% 6% 3 9% 7% 6% 7% 5% 8% 10% 29%	2090
	21st to end	Night	9% 6% 3 9% 5% 6% 7% 6% 8% 8% 33%	2090
October	1st to 10th	Night	9% 6% 3 8% 4 5% 5% 4 7% 9% 40%	2090
	11th to 20th	Night	6% 6% 2 6% 4 4 5% 4 7% 7% 49%	2255
	21st to end	Night	8% 5% 3 6% 3 4 4 3 6% 7% 51%	2508
November	1st to 10th	Night	7% 5% 1 6% 4 4 5% 4 6% 8% 50%	2341
	11th to 20th	Night	8% 6% 2 5% 5% 4 4 4 5% 7% 49%	2400
	21st to end	Night	8% 5% 2 6% 5% 4 4 3 5% 8% 50%	2505
December	1st to 10th	Night	7% 5% 2 5% 4 4 5% 4 6% 8% 51%	2581
	11th to 20th	Night	11% 6% 2 5% 4 4 4 4 6% 8% 47%	3042
	21st to end	Night	12% 7% 3 8% 5% 5% 5% 4 6% 8% 36%	4532

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	40% 6% 7% 21% 19% 7%	2837
	11th to 20th	Day	49% 4 5% 18% 18% 6%	2840
	21st to end	Day	37% 6% 8% 20% 22% 7%	3359
February	1st to 10th	Day	36% 6% 8% 21% 19% 11%	1900
	11th to 20th	Day	27% 5% 10% 21% 24% 12%	1858
	21st to end	Day	31% 5% 10% 18% 26% 11%	1652
March	1st to 10th	Day	40% 8% 13% 19% 14% 6%	3435
	11th to 20th	Day	28% 5% 13% 29% 20% 6%	3480
	21st to end	Day	28% 6% 8% 30% 18% 10%	3815
April	1st to 10th	Day	28% 7% 15% 25% 17% 7%	2090
	11th to 20th	Day	35% 6% 12% 19% 21% 6%	2066
	21st to end	Day	27% 5% 10% 25% 25% 8%	2256
May	1st to 10th	Day	20% 8% 14% 32% 20% 6%	4075
	11th to 20th	Day	34% 8% 18% 25% 14% 1	4085
	21st to end	Day	26% 8% 12% 32% 20% 2	4489
June	1st to 10th	Day	53% 10% 18% 15% 4	2470
	11th to 20th	Day	48% 12% 20% 17% 3	2470
	21st to end	Day	50% 12% 23% 13% 2 1	2470
July	1st to 10th	Day	47% 15% 29% 9% 1	4055
	11th to 20th	Day	43% 17% 32% 7%	4051
	21st to end	Day	46% 18% 25% 10% 1	4324
August	1st to 10th	Day	46% 13% 29% 9% 2	4091
	11th to 20th	Day	39% 14% 26% 15% 6%	3713
	21st to end	Day	44% 17% 27% 11% 1	3828
September	1st to 10th	Day	51% 15% 21% 11% 2	2090
	11th to 20th	Day	52% 12% 19% 13% 3	2090
	21st to end	Day	47% 10% 16% 16% 9% 2	2090
October	1st to 10th	Day	52% 11% 15% 10% 7% 4	3480
	11th to 20th	Day	27% 7% 11% 21% 30% 4	3177
	21st to end	Day	28% 6% 9% 24% 26% 8%	3428
November	1st to 10th	Day	31% 6% 11% 22% 19% 11%	1957
	11th to 20th	Day	35% 5% 9% 21% 20% 9%	2000
	21st to end	Day	33% 6% 11% 21% 20% 10%	1892
December	1st to 10th	Day	33% 5% 13% 25% 18% 7%	1782
	11th to 20th	Day	35% 5% 11% 20% 17% 12%	2150
	21st to end	Day	47% 6% 10% 18% 14% 4	3124
January	1st to 10th	Night	43% 5% 10% 20% 17% 5%	4109
	11th to 20th	Night	53% 5% 8% 19% 11% 4	4120
	21st to end	Night	40% 8% 11% 17% 19% 6%	4280
February	1st to 10th	Night	36% 6% 11% 19% 20% 8%	2280
	11th to 20th	Night	29% 5% 12% 21% 23% 10%	2219
	21st to end	Night	28% 5% 14% 21% 24% 8%	1799
March	1st to 10th	Night	44% 7% 13% 17% 15% 5%	3418
	11th to 20th	Night	25% 7% 24% 26% 15% 4	3480
	21st to end	Night	30% 5% 10% 25% 22% 7%	3817
April	1st to 10th	Night	24% 6% 19% 27% 16% 7%	2090
	11th to 20th	Night	27% 7% 17% 23% 22% 5%	2063
	21st to end	Night	25% 6% 13% 26% 24% 6%	1920
May	1st to 10th	Night	22% 11% 17% 29% 16% 5%	2912
	11th to 20th	Night	27% 9% 23% 29% 11% 1	2813
	21st to end	Night	21% 9% 16% 35% 18% 1	3087
June	1st to 10th	Night	39% 10% 24% 22% 6%	1710
	11th to 20th	Night	37% 13% 28% 19% 4	1710
	21st to end	Night	39% 16% 24% 14% 5%	1710
July	1st to 10th	Night	47% 15% 29% 8% 1	2795
	11th to 20th	Night	44% 19% 29% 7%	2786
	21st to end	Night	57% 16% 20% 8%	2988
August	1st to 10th	Night	39% 15% 30% 11% 5%	2814
	11th to 20th	Night	35% 16% 31% 15% 3	3141
	21st to end	Night	43% 17% 31% 8% 1	3828
September	1st to 10th	Night	42% 18% 25% 13% 2	2090
	11th to 20th	Night	48% 13% 22% 15% 2	2090
	21st to end	Night	44% 12% 18% 16% 9% 1	2090
October	1st to 10th	Night	55% 11% 12% 11% 8% 4	3480
	11th to 20th	Night	26% 8% 11% 29% 23% 4	3741
	21st to end	Night	29% 5% 9% 27% 25% 6%	4120
November	1st to 10th	Night	30% 6% 12% 21% 20% 10%	2341
	11th to 20th	Night	33% 7% 10% 23% 19% 9%	2400
	21st to end	Night	33% 5% 10% 22% 21% 9%	2505
December	1st to 10th	Night	30% 5% 14% 28% 17% 6%	2581
	11th to 20th	Night	34% 6% 11% 21% 16% 13%	3044
	21st to end	Night	44% 7% 14% 16% 15% 4	4532

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	11% 11% 35% 30% 11% 1	270
	11th to 20th	Day	9% 10% 35% 31% 11% 4	270
	21st to end	Day	15% 13% 39% 25% 6% 1	297
February	1st to 10th	Day	11% 8% 30% 32% 16% 3	270
	11th to 20th	Day	7% 9% 33% 29% 18% 5%	270
	21st to end	Day	7% 7% 26% 37% 20% 4	307
March	1st to 10th	Day	6% 5% 37% 35% 15% 2	460
	11th to 20th	Day	7% 7% 25% 31% 25% 4	460
	21st to end	Day	7% 5% 27% 35% 22% 5%	506
April	1st to 10th	Day	5% 6% 32% 33% 21% 3	460
	11th to 20th	Day	8% 8% 24% 33% 21% 7%	452
	21st to end	Day	5% 4 20% 29% 32% 9%	460
May	1st to 10th	Day	4 3 12% 33% 33% 15%	463
	11th to 20th	Day	10% 3 14% 27% 29% 17%	487
	21st to end	Day	7% 2 6% 21% 34% 30%	529
June	1st to 10th	Day	15% 4 6% 20% 28% 27%	490
	11th to 20th	Day	8% 2 7% 18% 27% 39%	490
	21st to end	Day	5% 2 3 9% 28% 53%	490
July	1st to 10th	Day	6% 1 3 9% 20% 61%	485
	11th to 20th	Day	4 1 2 11% 30% 53%	484
	21st to end	Day	11% 1 2 12% 24% 51%	532
August	1st to 10th	Day	7% 2 4 10% 28% 48%	486
	11th to 20th	Day	6% 1 3 9% 27% 54%	479
	21st to end	Day	9% 3 5% 14% 31% 38%	539
September	1st to 10th	Day	7% 3 5% 11% 31% 44%	490
	11th to 20th	Day	7% 3 6% 18% 32% 34%	490
	21st to end	Day	7% 2 5% 20% 36% 30%	490
October	1st to 10th	Day	11% 3 12% 30% 32% 11%	490
	11th to 20th	Day	6% 4 15% 33% 30% 11%	490
	21st to end	Day	8% 3 17% 37% 28% 7%	539
November	1st to 10th	Day	10% 6% 18% 31% 29% 7%	495
	11th to 20th	Day	12% 5% 20% 35% 23% 5%	500
	21st to end	Day	9% 5% 25% 34% 22% 5%	392
December	1st to 10th	Day	5% 9% 30% 33% 15% 7%	294
	11th to 20th	Day	10% 6% 30% 33% 18% 2	270
	21st to end	Day	6% 8% 26% 33% 21% 5%	297
January	1st to 10th	Night	10% 7% 27% 40% 16%	760
	11th to 20th	Night	12% 6% 24% 44% 14% 1	760
	21st to end	Night	13% 8% 32% 36% 11%	836
February	1st to 10th	Night	12% 6% 27% 40% 14%	760
	11th to 20th	Night	10% 5% 27% 43% 15% 1	743
	21st to end	Night	9% 4 25% 48% 13% 1	628
March	1st to 10th	Night	6% 5% 32% 45% 11% 1	760
	11th to 20th	Night	7% 5% 26% 43% 17% 1	760
	21st to end	Night	6% 4 27% 46% 15% 1	836
April	1st to 10th	Night	6% 4 26% 46% 19%	760
	11th to 20th	Night	6% 4 25% 46% 18% 1	751
	21st to end	Night	6% 3 24% 45% 22%	760
May	1st to 10th	Night	3 2 12% 49% 31% 3	616
	11th to 20th	Night	7% 2 11% 43% 33% 4	561
	21st to end	Night	5% 2 7% 35% 44% 8%	617
June	1st to 10th	Night	10% 1 5% 28% 46% 10%	570
	11th to 20th	Night	5% 2 5% 18% 46% 24%	570
	21st to end	Night	6% 1 2 13% 45% 33%	570
July	1st to 10th	Night	7% 2 2 8% 46% 35%	555
	11th to 20th	Night	5% 1 2 7% 47% 38%	552
	21st to end	Night	5% 2 2 7% 49% 35%	624
August	1st to 10th	Night	5% 2 2 10% 47% 34%	567
	11th to 20th	Night	4 1 2 8% 40% 44%	579
	21st to end	Night	11% 3 5% 19% 37% 25%	836
September	1st to 10th	Night	8% 2 4 18% 47% 22%	760
	11th to 20th	Night	11% 4 5% 22% 40% 19%	760
	21st to end	Night	11% 4 5% 26% 42% 13%	760
October	1st to 10th	Night	13% 3 12% 39% 29% 5%	760
	11th to 20th	Night	7% 4 14% 35% 38% 3	760
	21st to end	Night	10% 3 16% 41% 28% 2	836
November	1st to 10th	Night	9% 4 20% 41% 22% 4	780
	11th to 20th	Night	9% 5% 19% 43% 23% 2	800
	21st to end	Night	9% 2 24% 45% 19% 1	800
December	1st to 10th	Night	8% 3 24% 40% 24% 1	795
	11th to 20th	Night	10% 5% 22% 40% 22% 1	760
	21st to end	Night	8% 5% 24% 41% 21% 1	836

Page generated at 2024-12-06 03:54:47. Version ac07

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