Doughton Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Doughton Park clear sky chart from 2005-11-06 to 2024-11-05.

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	15% 6% 2 6% 5% 5% 5% 4 6% 8% 39%	101211
	Night	15% 6% 2 5% 4 4 4 4 5% 7% 44%	97770
Transparency	Day	40% 8% 13% 20% 14% 5%	104914
	Night	37% 8% 13% 21% 16% 5%	102206
Seeing	Day	20% 14% 25% 22% 13% 6%	15197
	Night	18% 12% 24% 27% 17% 3	25261

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	16% 5% 1 4 3 3 3 3 4 6% 51%	2836
	11th to 20th	Day	14% 7% 2 5% 4 4 4 3 5% 5% 46%	2840
	21st to end	Day	23% 6% 2 5% 3 3 3 2 4 5% 43%	3124
February	1st to 10th	Day	12% 9% 2 6% 4 5% 3 4 6% 6% 41%	1710
	11th to 20th	Day	17% 8% 3 5% 4 3 4 4 5% 5% 41%	1805
	21st to end	Day	19% 7% 2 6% 4 4 4 4 5% 6% 39%	1589
March	1st to 10th	Day	24% 7% 2 5% 3 3 4 3 5% 6% 39%	3435
	11th to 20th	Day	12% 5% 2 5% 3 4 3 3 5% 6% 52%	3480
	21st to end	Day	20% 7% 2 5% 3 3 4 3 5% 6% 41%	3815
April	1st to 10th	Day	12% 5% 1 5% 4 4 4 4 6% 7% 48%	2090
	11th to 20th	Day	17% 6% 2 5% 4 3 4 4 6% 7% 43%	2262
	21st to end	Day	15% 6% 2 5% 5% 4 5% 4 5% 6% 42%	2470
May	1st to 10th	Day	16% 7% 3 7% 5% 5% 6% 4 7% 8% 32%	4082
	11th to 20th	Day	19% 7% 2 7% 5% 5% 5% 4 6% 8% 31%	4081
	21st to end	Day	10% 5% 2 6% 5% 5% 5% 5% 7% 9% 40%	4476
June	1st to 10th	Day	13% 6% 2 6% 6% 6% 6% 4 7% 9% 34%	2470
	11th to 20th	Day	10% 6% 2 6% 6% 6% 6% 5% 7% 11% 34%	2470
	21st to end	Day	9% 5% 2 7% 6% 6% 5% 6% 9% 10% 34%	2470
July	1st to 10th	Day	8% 5% 2 7% 6% 6% 7% 7% 9% 10% 34%	4120
	11th to 20th	Day	9% 6% 2 8% 6% 7% 8% 5% 8% 11% 29%	4120
	21st to end	Day	14% 9% 4 10% 9% 7% 7% 6% 7% 8% 19%	4466
August	1st to 10th	Day	15% 8% 3 8% 6% 6% 6% 6% 8% 10% 24%	4104
	11th to 20th	Day	10% 5% 2 8% 5% 7% 7% 5% 9% 10% 32%	4044
	21st to end	Day	8% 4 2 5% 4 5% 5% 5% 7% 10% 46%	4294
September	1st to 10th	Day	13% 6% 2 6% 5% 5% 5% 5% 6% 7% 41%	2121
	11th to 20th	Day	18% 7% 3 7% 4 4 5% 4 6% 8% 35%	2090
	21st to end	Day	23% 7% 2 6% 5% 4 4 3 5% 6% 36%	2090
October	1st to 10th	Day	17% 5% 2 5% 4 3 3 3 4 6% 49%	1976
	11th to 20th	Day	14% 5% 1 5% 3 4 3 3 4 7% 52%	1900
	21st to end	Day	16% 5% 1 5% 3 2 2 2 4 6% 54%	2090
November	1st to 10th	Day	13% 5% 2 4 4 2 3 3 4 6% 55%	1884
	11th to 20th	Day	13% 5% 1 4 3 3 3 3 5% 6% 53%	1710
	21st to end	Day	15% 6% 2 5% 4 2 4 3 4 6% 49%	1710
December	1st to 10th	Day	17% 10% 3 6% 5% 4 4 4 4 6% 38%	1710
	11th to 20th	Day	15% 4 2 4 3 4 3 2 5% 7% 51%	2153
	21st to end	Day	21% 6% 2 5% 3 4 4 4 6% 7% 39%	3124
January	1st to 10th	Night	15% 7% 1 5% 3 4 4 3 5% 6% 48%	4109
	11th to 20th	Night	13% 8% 2 5% 4 4 4 3 5% 6% 48%	4120
	21st to end	Night	23% 8% 2 4 3 3 3 3 4 5% 42%	4532
February	1st to 10th	Night	13% 7% 3 5% 4 4 4 5% 6% 6% 44%	2470
	11th to 20th	Night	19% 7% 3 5% 3 3 4 3 5% 6% 43%	2256
	21st to end	Night	16% 7% 2 7% 5% 4 4 4 5% 6% 40%	1863
March	1st to 10th	Night	26% 9% 2 5% 3 4 4 3 4 5% 35%	3418
	11th to 20th	Night	10% 3 1 5% 3 4 4 4 5% 7% 54%	3480
	21st to end	Night	18% 6% 1 4 3 4 4 3 5% 7% 44%	3817
April	1st to 10th	Night	12% 7% 2 5% 4 4 4 3 5% 8% 46%	2090
	11th to 20th	Night	16% 5% 2 4 4 3 3 3 6% 8% 46%	1875
	21st to end	Night	16% 5% 2 4 3 3 4 4 5% 7% 48%	1714
May	1st to 10th	Night	17% 8% 1 6% 4 4 4 4 5% 8% 38%	2813
	11th to 20th	Night	21% 7% 2 5% 3 3 3 3 5% 8% 40%	2812
	21st to end	Night	12% 5% 2 6% 3 3 4 4 8% 10% 44%	3079
June	1st to 10th	Night	11% 5% 2 5% 4 4 6% 5% 7% 10% 40%	1710
	11th to 20th	Night	11% 6% 2 4 4 5% 4 4 7% 9% 43%	1710
	21st to end	Night	8% 6% 2 6% 5% 4 4 4 8% 10% 43%	1710
July	1st to 10th	Night	10% 5% 2 7% 5% 4 5% 6% 9% 10% 38%	2840
	11th to 20th	Night	9% 5% 2 6% 4 5% 4 5% 9% 11% 39%	2840
	21st to end	Night	11% 9% 4 9% 7% 6% 6% 5% 7% 9% 26%	3087
August	1st to 10th	Night	14% 8% 4 8% 4 5% 5% 4 7% 10% 30%	2825
	11th to 20th	Night	11% 6% 2 7% 5% 5% 5% 5% 7% 10% 37%	2785
	21st to end	Night	7% 4 1 5% 4 4 4 4 6% 9% 52%	3316
September	1st to 10th	Night	13% 5% 2 7% 3 4 4 4 6% 7% 45%	2055
	11th to 20th	Night	19% 7% 2 6% 4 4 3 3 6% 7% 40%	2090
	21st to end	Night	22% 6% 2 6% 4 4 4 3 4 5% 41%	2090
October	1st to 10th	Night	17% 7% 2 4 2 3 3 3 4 6% 49%	2203
	11th to 20th	Night	16% 4 2 4 3 3 3 2 4 6% 52%	2280
	21st to end	Night	15% 4 1 4 3 2 3 2 3 5% 57%	2508
November	1st to 10th	Night	16% 5% 2 4 3 2 3 3 4 5% 54%	2289
	11th to 20th	Night	15% 5% 1 3 3 3 3 3 4 6% 54%	2470
	21st to end	Night	14% 5% 2 4 3 3 4 3 5% 6% 50%	2470
December	1st to 10th	Night	18% 8% 2 6% 3 3 3 3 4 6% 44%	2470
	11th to 20th	Night	15% 6% 2 5% 3 3 4 3 4 7% 47%	3042
	21st to end	Night	23% 8% 2 5% 3 3 4 4 6% 7% 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	33% 6% 9% 24% 22% 5%	2837
	11th to 20th	Day	37% 7% 9% 18% 24% 5%	2840
	21st to end	Day	43% 5% 9% 20% 20% 4	3124
February	1st to 10th	Day	40% 7% 12% 19% 17% 4	1710
	11th to 20th	Day	43% 5% 11% 19% 18% 5%	1815
	21st to end	Day	43% 7% 12% 15% 16% 6%	1589
March	1st to 10th	Day	42% 7% 12% 18% 13% 8%	3435
	11th to 20th	Day	32% 7% 9% 23% 19% 10%	3480
	21st to end	Day	42% 6% 11% 22% 15% 4	3815
April	1st to 10th	Day	32% 8% 13% 22% 19% 5%	2090
	11th to 20th	Day	38% 7% 13% 19% 18% 6%	2262
	21st to end	Day	41% 8% 13% 21% 13% 3	2470
May	1st to 10th	Day	44% 14% 13% 18% 10% 1	4120
	11th to 20th	Day	46% 12% 13% 19% 8% 1	4085
	21st to end	Day	33% 14% 16% 20% 14% 3	4489
June	1st to 10th	Day	42% 13% 16% 18% 10% 1	2470
	11th to 20th	Day	41% 12% 14% 18% 12% 2	2470
	21st to end	Day	40% 12% 17% 18% 13% 1	2470
July	1st to 10th	Day	42% 12% 18% 17% 7% 3	4055
	11th to 20th	Day	47% 9% 23% 15% 5% 1	4051
	21st to end	Day	59% 11% 12% 13% 4 1	4324
August	1st to 10th	Day	52% 9% 18% 18% 4	4091
	11th to 20th	Day	42% 11% 21% 17% 6% 3	4083
	21st to end	Day	33% 9% 19% 29% 8% 2	4294
September	1st to 10th	Day	39% 11% 13% 19% 15% 4	2121
	11th to 20th	Day	45% 8% 12% 18% 15% 1	2090
	21st to end	Day	49% 6% 12% 17% 14% 3	2090
October	1st to 10th	Day	29% 6% 8% 20% 26% 11%	3288
	11th to 20th	Day	23% 4 7% 23% 21% 22%	3140
	21st to end	Day	26% 4 10% 26% 17% 17%	3428
November	1st to 10th	Day	31% 5% 10% 22% 25% 7%	1884
	11th to 20th	Day	31% 5% 11% 20% 27% 6%	1710
	21st to end	Day	35% 4 10% 21% 25% 5%	1710
December	1st to 10th	Day	47% 6% 9% 18% 15% 5%	1710
	11th to 20th	Day	32% 5% 11% 21% 23% 8%	2150
	21st to end	Day	40% 7% 12% 22% 15% 3	3124
January	1st to 10th	Night	34% 8% 13% 21% 18% 6%	4109
	11th to 20th	Night	37% 8% 9% 17% 22% 7%	4120
	21st to end	Night	43% 7% 8% 17% 19% 6%	4532
February	1st to 10th	Night	38% 7% 12% 22% 18% 3	2470
	11th to 20th	Night	42% 6% 9% 20% 16% 6%	2257
	21st to end	Night	42% 7% 13% 19% 14% 5%	1863
March	1st to 10th	Night	48% 8% 11% 16% 13% 4	3418
	11th to 20th	Night	29% 7% 9% 23% 21% 11%	3480
	21st to end	Night	37% 7% 12% 24% 14% 6%	3817
April	1st to 10th	Night	35% 8% 12% 22% 18% 4	2090
	11th to 20th	Night	35% 7% 12% 21% 18% 6%	1875
	21st to end	Night	35% 8% 15% 25% 15% 3	1714
May	1st to 10th	Night	42% 11% 15% 23% 9% 1	2840
	11th to 20th	Night	43% 10% 15% 23% 8% 1	2813
	21st to end	Night	30% 12% 20% 25% 11% 2	3087
June	1st to 10th	Night	34% 14% 18% 22% 11% 1	1710
	11th to 20th	Night	34% 11% 19% 24% 11% 1	1710
	21st to end	Night	32% 12% 20% 21% 12% 3	1710
July	1st to 10th	Night	38% 13% 17% 21% 9% 1	2795
	11th to 20th	Night	35% 12% 26% 22% 5% 1	2786
	21st to end	Night	51% 11% 17% 16% 5%	2988
August	1st to 10th	Night	47% 8% 22% 17% 6%	2814
	11th to 20th	Night	40% 7% 24% 19% 9% 1	2812
	21st to end	Night	28% 8% 19% 35% 8% 2	3316
September	1st to 10th	Night	37% 10% 16% 18% 16% 4	2055
	11th to 20th	Night	42% 8% 14% 18% 18% 1	2090
	21st to end	Night	46% 7% 10% 18% 15% 3	2090
October	1st to 10th	Night	32% 6% 8% 19% 22% 13%	3671
	11th to 20th	Night	22% 4 8% 22% 24% 19%	3779
	21st to end	Night	26% 3 9% 24% 22% 17%	4120
November	1st to 10th	Night	34% 5% 10% 21% 23% 7%	2289
	11th to 20th	Night	31% 5% 9% 21% 25% 9%	2470
	21st to end	Night	34% 5% 9% 24% 23% 5%	2470
December	1st to 10th	Night	42% 6% 10% 20% 16% 5%	2470
	11th to 20th	Night	36% 6% 11% 18% 24% 5%	3044
	21st to end	Night	42% 8% 15% 20% 14% 2	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	30% 29% 29% 9% 3	270
	11th to 20th	Day	34% 24% 31% 10%	270
	21st to end	Day	29% 34% 27% 7% 2	297
February	1st to 10th	Day	30% 28% 25% 17% 1	270
	11th to 20th	Day	42% 26% 27% 4	270
	21st to end	Day	35% 29% 29% 7%	244
March	1st to 10th	Day	25% 24% 29% 16% 6%	460
	11th to 20th	Day	26% 26% 31% 12% 3 1	460
	21st to end	Day	28% 24% 28% 15% 5% 1	506
April	1st to 10th	Day	24% 23% 29% 16% 7% 1	460
	11th to 20th	Day	21% 23% 26% 17% 10% 3	452
	21st to end	Day	22% 18% 28% 19% 9% 3	460
May	1st to 10th	Day	20% 18% 33% 17% 8% 4	463
	11th to 20th	Day	17% 14% 26% 25% 12% 6%	487
	21st to end	Day	18% 6% 25% 25% 17% 9%	529
June	1st to 10th	Day	13% 8% 26% 30% 16% 8%	490
	11th to 20th	Day	11% 7% 23% 28% 21% 9%	490
	21st to end	Day	12% 7% 27% 32% 13% 8%	490
July	1st to 10th	Day	11% 3 17% 30% 27% 12%	485
	11th to 20th	Day	8% 2 18% 31% 29% 13%	484
	21st to end	Day	13% 2 19% 30% 24% 12%	532
August	1st to 10th	Day	17% 4 24% 23% 16% 15%	486
	11th to 20th	Day	11% 3 22% 28% 23% 14%	479
	21st to end	Day	10% 4 14% 33% 24% 15%	539
September	1st to 10th	Day	15% 4 16% 30% 24% 12%	490
	11th to 20th	Day	19% 5% 16% 25% 25% 11%	490
	21st to end	Day	23% 11% 19% 27% 15% 5%	490
October	1st to 10th	Day	23% 7% 21% 24% 19% 6%	490
	11th to 20th	Day	17% 16% 24% 24% 16% 2	490
	21st to end	Day	20% 13% 30% 25% 9% 3	539
November	1st to 10th	Day	20% 14% 27% 25% 10% 3	458
	11th to 20th	Day	20% 25% 29% 20% 5% 1	270
	21st to end	Day	19% 22% 33% 21% 4 1	270
December	1st to 10th	Day	26% 26% 34% 11% 3	270
	11th to 20th	Day	22% 21% 36% 16% 4	270
	21st to end	Day	31% 18% 35% 12% 4 1	297
January	1st to 10th	Night	19% 23% 33% 20% 4	760
	11th to 20th	Night	22% 21% 32% 22% 3	760
	21st to end	Night	19% 22% 35% 21% 3	836
February	1st to 10th	Night	17% 19% 34% 27% 3	760
	11th to 20th	Night	26% 27% 32% 15% 1	743
	21st to end	Night	20% 22% 37% 19% 2	628
March	1st to 10th	Night	19% 21% 32% 24% 3	760
	11th to 20th	Night	24% 17% 31% 21% 6% 1	760
	21st to end	Night	20% 18% 33% 23% 6%	836
April	1st to 10th	Night	18% 20% 30% 25% 7%	760
	11th to 20th	Night	20% 19% 25% 26% 10% 1	751
	21st to end	Night	17% 11% 29% 32% 10%	574
May	1st to 10th	Night	18% 9% 29% 29% 14%	570
	11th to 20th	Night	17% 9% 20% 34% 17% 3	561
	21st to end	Night	18% 4 16% 29% 29% 5%	617
June	1st to 10th	Night	12% 4 17% 35% 29% 5%	570
	11th to 20th	Night	12% 2 18% 30% 32% 5%	570
	21st to end	Night	9% 2 14% 38% 34% 4	570
July	1st to 10th	Night	12% 2 9% 28% 43% 6%	555
	11th to 20th	Night	9% 2 7% 31% 44% 7%	552
	21st to end	Night	7% 2 9% 34% 41% 7%	624
August	1st to 10th	Night	16% 2 13% 30% 35% 5%	567
	11th to 20th	Night	15% 3 11% 29% 34% 8%	564
	21st to end	Night	14% 1 10% 29% 37% 9%	741
September	1st to 10th	Night	13% 4 13% 27% 35% 8%	760
	11th to 20th	Night	20% 3 13% 28% 30% 6%	760
	21st to end	Night	26% 5% 16% 29% 23% 2	760
October	1st to 10th	Night	18% 9% 21% 23% 22% 6%	760
	11th to 20th	Night	19% 9% 24% 29% 16% 2	760
	21st to end	Night	18% 12% 21% 33% 14% 2	836
November	1st to 10th	Night	18% 11% 25% 30% 14% 3	760
	11th to 20th	Night	17% 14% 26% 32% 9% 1	760
	21st to end	Night	16% 17% 26% 29% 10% 1	760
December	1st to 10th	Night	22% 18% 29% 24% 6%	760
	11th to 20th	Night	19% 16% 33% 26% 6% 1	760
	21st to end	Night	27% 17% 24% 27% 4	836

Page generated at 2024-11-03 02:11:13. Version ac07

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