Veasey Memorial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Veasey Memorial Park clear sky chart from 2005-11-06 to 2025-10-19.

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	17% 7% 2 6% 4 4 4 4 5% 7% 38%	126324
	Night	17% 8% 2 6% 4 4 4 3 5% 6% 39%	123378
Transparency	Day	44% 6% 12% 22% 15% 2	129844
	Night	44% 5% 11% 21% 16% 2	127932
Seeing	Day	21% 15% 33% 21% 8% 2	16266
	Night	21% 13% 33% 25% 7% 1	25084

By Month

Percentage Cloud Cover NE (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	13% 7% 3 8% 4 4 5% 4 6% 7% 39%	3597
	11th to 20th	Day	14% 7% 3 6% 3 3 4 3 4 6% 47%	3570
	21st to end	Day	16% 9% 2 5% 4 4 3 3 4 5% 45%	3960
February	1st to 10th	Day	17% 8% 3 6% 4 4 5% 5% 5% 7% 37%	1845
	11th to 20th	Day	14% 7% 3 7% 4 5% 5% 4 6% 7% 39%	1948
	21st to end	Day	17% 11% 3 6% 5% 4 4 4 5% 5% 37%	1650
March	1st to 10th	Day	21% 11% 3 6% 4 4 4 3 5% 6% 34%	4476
	11th to 20th	Day	16% 9% 3 7% 4 4 4 4 6% 6% 38%	4795
	21st to end	Day	26% 9% 3 6% 3 3 4 4 5% 6% 30%	5732
April	1st to 10th	Day	20% 10% 3 7% 4 3 3 3 5% 6% 37%	2400
	11th to 20th	Day	18% 7% 2 5% 5% 4 5% 4 5% 6% 38%	2408
	21st to end	Day	21% 6% 2 6% 5% 4 4 3 5% 7% 37%	2600
May	1st to 10th	Day	30% 10% 2 7% 4 4 4 3 5% 7% 24%	5886
	11th to 20th	Day	19% 9% 3 8% 5% 4 4 4 5% 7% 31%	5949
	21st to end	Day	19% 7% 3 6% 4 4 5% 4 5% 8% 36%	6949
June	1st to 10th	Day	20% 7% 2 5% 4 4 5% 4 7% 8% 34%	2800
	11th to 20th	Day	17% 6% 2 6% 4 4 5% 4 6% 8% 39%	2800
	21st to end	Day	18% 7% 2 6% 5% 4 5% 4 7% 8% 35%	2800
July	1st to 10th	Day	17% 7% 3 6% 4 5% 5% 4 7% 9% 33%	6360
	11th to 20th	Day	9% 6% 2 7% 5% 5% 5% 4 7% 11% 40%	6360
	21st to end	Day	15% 6% 2 6% 4 4 4 3 6% 8% 43%	6926
August	1st to 10th	Day	15% 5% 3 7% 5% 5% 5% 5% 7% 8% 34%	4274
	11th to 20th	Day	14% 8% 3 6% 4 4 5% 4 6% 8% 38%	4175
	21st to end	Day	8% 4 2 5% 5% 5% 6% 5% 7% 10% 45%	4313
September	1st to 10th	Day	13% 5% 2 5% 4 4 4 3 6% 6% 47%	2385
	11th to 20th	Day	14% 6% 2 5% 3 3 3 3 4 6% 51%	2200
	21st to end	Day	18% 6% 2 5% 4 3 3 3 5% 7% 44%	2200
October	1st to 10th	Day	21% 5% 2 5% 4 4 4 4 4 5% 42%	2200
	11th to 20th	Day	16% 5% 2 5% 4 4 4 4 5% 6% 46%	1930
	21st to end	Day	21% 7% 2 6% 4 4 4 3 5% 5% 40%	1881
November	1st to 10th	Day	15% 6% 2 5% 4 3 3 3 3 5% 50%	1761
	11th to 20th	Day	18% 7% 2 4 3 2 4 3 4 5% 47%	1800
	21st to end	Day	19% 7% 2 5% 3 4 3 3 5% 6% 42%	1800
December	1st to 10th	Day	14% 9% 2 5% 3 3 3 3 4 6% 47%	2648
	11th to 20th	Day	20% 6% 2 5% 4 3 3 3 4 5% 47%	2986
	21st to end	Day	21% 10% 3 6% 4 3 4 3 4 5% 38%	3960
January	1st to 10th	Night	14% 6% 2 5% 4 4 4 4 5% 6% 46%	6349
	11th to 20th	Night	13% 8% 3 8% 5% 5% 4 4 5% 6% 39%	6315
	21st to end	Night	15% 10% 3 7% 5% 5% 5% 3 5% 5% 38%	6996
February	1st to 10th	Night	16% 9% 3 6% 5% 4 5% 4 5% 6% 38%	2551
	11th to 20th	Night	15% 9% 3 5% 4 5% 4 4 6% 6% 40%	2338
	21st to end	Night	17% 9% 2 5% 4 3 4 3 6% 5% 42%	1980
March	1st to 10th	Night	24% 8% 2 6% 3 3 4 3 5% 5% 36%	5364
	11th to 20th	Night	16% 9% 3 8% 4 5% 5% 3 5% 6% 36%	5163
	21st to end	Night	26% 8% 2 6% 4 4 4 3 5% 5% 32%	5197
April	1st to 10th	Night	19% 9% 3 7% 5% 4 4 3 5% 6% 35%	2000
	11th to 20th	Night	21% 8% 2 6% 4 4 4 3 4 6% 40%	1940
	21st to end	Night	21% 6% 3 6% 4 5% 4 3 5% 5% 38%	1800
May	1st to 10th	Night	32% 10% 3 6% 4 4 4 3 4 6% 25%	4054
	11th to 20th	Night	16% 9% 3 8% 6% 5% 6% 5% 7% 7% 28%	3973
	21st to end	Night	21% 8% 3 8% 5% 4 4 3 5% 6% 32%	3926
June	1st to 10th	Night	18% 8% 2 7% 6% 4 4 3 5% 7% 36%	1600
	11th to 20th	Night	19% 7% 2 5% 4 4 4 4 6% 9% 36%	1600
	21st to end	Night	16% 7% 2 6% 5% 4 4 4 6% 8% 37%	1600
July	1st to 10th	Night	13% 7% 2 8% 4 4 5% 4 6% 9% 37%	3600
	11th to 20th	Night	10% 6% 3 8% 4 5% 5% 4 6% 10% 38%	3600
	21st to end	Night	12% 6% 2 7% 4 4 4 4 5% 7% 46%	3926
August	1st to 10th	Night	20% 7% 2 7% 5% 5% 5% 4 6% 7% 34%	2841
	11th to 20th	Night	11% 8% 3 8% 5% 5% 6% 5% 6% 8% 34%	2872
	21st to end	Night	9% 4 2 5% 3 4 4 3 5% 9% 52%	3581
September	1st to 10th	Night	13% 6% 2 5% 4 3 3 3 5% 7% 48%	2015
	11th to 20th	Night	13% 5% 1 5% 3 3 3 2 4 6% 53%	2200
	21st to end	Night	17% 6% 2 6% 4 3 4 3 6% 6% 44%	2200
October	1st to 10th	Night	20% 5% 2 6% 4 4 3 3 4 6% 42%	2200
	11th to 20th	Night	16% 5% 1 6% 3 4 4 3 6% 6% 46%	2425
	21st to end	Night	22% 7% 2 5% 3 4 4 4 5% 6% 39%	2717
November	1st to 10th	Night	14% 5% 2 5% 5% 4 4 3 4 6% 48%	2537
	11th to 20th	Night	17% 6% 2 5% 3 4 4 3 4 5% 47%	2600
	21st to end	Night	16% 7% 2 5% 4 4 3 3 5% 6% 44%	2600
December	1st to 10th	Night	17% 8% 3 6% 4 4 4 4 5% 5% 40%	4514
	11th to 20th	Night	23% 6% 2 5% 4 3 3 3 5% 5% 41%	5208
	21st to end	Night	18% 10% 3 6% 4 3 4 3 4 5% 40%	6996

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	42% 4 9% 27% 17% 1	3598
	11th to 20th	Day	38% 4 12% 23% 20% 3	3600
	21st to end	Day	43% 4 9% 22% 19% 3	3960
February	1st to 10th	Day	46% 5% 12% 20% 14% 2	1845
	11th to 20th	Day	44% 6% 12% 20% 15% 3	1957
	21st to end	Day	47% 5% 11% 20% 14% 3	1650
March	1st to 10th	Day	51% 4 9% 15% 12% 10%	4479
	11th to 20th	Day	44% 5% 14% 24% 11% 2	4795
	21st to end	Day	53% 4 6% 15% 14% 7%	5732
April	1st to 10th	Day	49% 5% 9% 17% 17% 4	2400
	11th to 20th	Day	45% 5% 12% 19% 16% 3	2408
	21st to end	Day	47% 6% 7% 19% 17% 4	2600
May	1st to 10th	Day	60% 6% 12% 14% 7% 1	5897
	11th to 20th	Day	51% 7% 14% 17% 10% 2	5953
	21st to end	Day	45% 7% 12% 21% 13% 1	6949
June	1st to 10th	Day	47% 7% 13% 21% 12% 1	2800
	11th to 20th	Day	42% 6% 15% 20% 15% 3	2800
	21st to end	Day	45% 7% 13% 22% 12% 1	2800
July	1st to 10th	Day	46% 7% 12% 20% 14% 1	6290
	11th to 20th	Day	38% 6% 17% 26% 13% 1	6285
	21st to end	Day	39% 5% 12% 27% 15% 1	6728
August	1st to 10th	Day	44% 8% 16% 22% 9% 1	4260
	11th to 20th	Day	42% 8% 13% 27% 9% 1	4214
	21st to end	Day	30% 8% 13% 29% 18% 2	4313
September	1st to 10th	Day	35% 6% 12% 25% 21% 1	2385
	11th to 20th	Day	35% 4 9% 27% 23% 2	2200
	21st to end	Day	40% 6% 8% 23% 20% 2	2200
October	1st to 10th	Day	42% 5% 10% 23% 18% 3	3590
	11th to 20th	Day	32% 4 8% 29% 24% 3	3120
	21st to end	Day	34% 4 9% 31% 20% 3	3081
November	1st to 10th	Day	38% 5% 12% 27% 16% 2	1761
	11th to 20th	Day	40% 4 8% 22% 23% 3	1800
	21st to end	Day	43% 5% 14% 22% 14% 2	1800
December	1st to 10th	Day	40% 4 14% 29% 13% 1	2648
	11th to 20th	Day	42% 3 13% 18% 19% 5%	2986
	21st to end	Day	49% 4 9% 20% 14% 5%	3960
January	1st to 10th	Night	37% 4 11% 32% 14% 2	6349
	11th to 20th	Night	46% 5% 12% 21% 13% 3	6360
	21st to end	Night	48% 4 9% 17% 17% 5%	6996
February	1st to 10th	Night	46% 5% 13% 20% 14% 2	2551
	11th to 20th	Night	45% 4 11% 20% 16% 4	2340
	21st to end	Night	43% 4 9% 25% 14% 4	1980
March	1st to 10th	Night	49% 4 9% 15% 14% 8%	5374
	11th to 20th	Night	48% 6% 15% 17% 13% 2	5164
	21st to end	Night	53% 4 5% 13% 19% 6%	5197
April	1st to 10th	Night	49% 5% 10% 17% 16% 3	2000
	11th to 20th	Night	46% 4 8% 20% 19% 3	1940
	21st to end	Night	47% 5% 10% 18% 17% 3	1800
May	1st to 10th	Night	61% 5% 12% 12% 8% 2	4060
	11th to 20th	Night	51% 8% 15% 16% 9% 1	3974
	21st to end	Night	51% 7% 13% 17% 11% 1	3927
June	1st to 10th	Night	48% 6% 12% 22% 12% 1	1600
	11th to 20th	Night	43% 7% 15% 20% 14% 2	1600
	21st to end	Night	42% 9% 13% 21% 14% 1	1600
July	1st to 10th	Night	43% 6% 12% 22% 16%	3560
	11th to 20th	Night	40% 8% 18% 20% 15% 1	3552
	21st to end	Night	37% 6% 11% 31% 14% 1	3809
August	1st to 10th	Night	49% 8% 12% 19% 11% 1	2831
	11th to 20th	Night	44% 10% 14% 22% 10% 1	2899
	21st to end	Night	28% 7% 15% 27% 22% 1	3581
September	1st to 10th	Night	35% 6% 11% 26% 20% 1	2015
	11th to 20th	Night	33% 5% 10% 24% 26% 2	2200
	21st to end	Night	41% 5% 8% 25% 18% 2	2200
October	1st to 10th	Night	41% 5% 14% 23% 16% 2	3590
	11th to 20th	Night	28% 4 10% 29% 27% 3	3961
	21st to end	Night	34% 4 11% 31% 18% 2	4467
November	1st to 10th	Night	37% 6% 12% 23% 20% 3	2537
	11th to 20th	Night	40% 4 9% 23% 21% 3	2600
	21st to end	Night	41% 5% 14% 25% 14% 2	2600
December	1st to 10th	Night	45% 4 11% 28% 11% 1	4514
	11th to 20th	Night	46% 3 14% 15% 21% 1	5208
	21st to end	Night	46% 4 9% 22% 17% 2	6996

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	27% 23% 31% 17% 3	200
	11th to 20th	Day	24% 27% 35% 12% 3 1	200
	21st to end	Day	24% 24% 37% 12% 4	220
February	1st to 10th	Day	27% 22% 36% 14% 1	397
	11th to 20th	Day	28% 26% 34% 10% 2	496
	21st to end	Day	24% 21% 36% 15% 4	414
March	1st to 10th	Day	27% 19% 38% 13% 3	500
	11th to 20th	Day	24% 25% 34% 13% 2 1	500
	21st to end	Day	30% 21% 32% 11% 5% 2	550
April	1st to 10th	Day	29% 24% 27% 14% 5% 1	500
	11th to 20th	Day	27% 23% 32% 13% 5%	492
	21st to end	Day	26% 15% 37% 18% 4 1	500
May	1st to 10th	Day	30% 20% 32% 12% 5% 1	503
	11th to 20th	Day	20% 15% 40% 19% 5% 1	527
	21st to end	Day	19% 13% 34% 27% 6% 1	573
June	1st to 10th	Day	20% 11% 37% 21% 10% 1	530
	11th to 20th	Day	15% 14% 38% 25% 7% 1	530
	21st to end	Day	19% 11% 37% 25% 7% 2	530
July	1st to 10th	Day	18% 6% 33% 29% 12% 2	525
	11th to 20th	Day	13% 8% 31% 32% 14% 2	524
	21st to end	Day	12% 6% 36% 36% 10% 1	576
August	1st to 10th	Day	11% 7% 31% 36% 13% 3	526
	11th to 20th	Day	14% 7% 29% 31% 15% 4	519
	21st to end	Day	12% 8% 33% 30% 13% 4	583
September	1st to 10th	Day	15% 10% 31% 26% 14% 4	530
	11th to 20th	Day	17% 10% 30% 21% 15% 7%	530
	21st to end	Day	18% 12% 32% 25% 9% 5%	530
October	1st to 10th	Day	24% 14% 25% 23% 12% 3	530
	11th to 20th	Day	21% 15% 28% 24% 9% 2	452
	21st to end	Day	26% 12% 35% 18% 7% 1	429
November	1st to 10th	Day	16% 17% 35% 22% 8% 2	395
	11th to 20th	Day	25% 22% 30% 18% 5% 1	400
	21st to end	Day	28% 20% 29% 17% 6% 1	400
December	1st to 10th	Day	23% 24% 33% 16% 5%	235
	11th to 20th	Day	32% 20% 35% 11% 3	200
	21st to end	Day	22% 24% 32% 15% 5% 2	220
January	1st to 10th	Night	21% 20% 40% 16% 3	800
	11th to 20th	Night	25% 20% 36% 17% 2	800
	21st to end	Night	19% 21% 38% 18% 4	880
February	1st to 10th	Night	23% 18% 37% 21% 1	800
	11th to 20th	Night	22% 20% 41% 15% 2	783
	21st to end	Night	24% 18% 36% 19% 3	660
March	1st to 10th	Night	26% 18% 36% 19% 3	800
	11th to 20th	Night	22% 17% 39% 18% 4	800
	21st to end	Night	25% 17% 34% 20% 5%	880
April	1st to 10th	Night	25% 17% 34% 21% 3	800
	11th to 20th	Night	24% 17% 34% 20% 6%	756
	21st to end	Night	23% 13% 35% 26% 2 1	600
May	1st to 10th	Night	27% 11% 35% 21% 5% 1	600
	11th to 20th	Night	20% 12% 37% 25% 5% 1	571
	21st to end	Night	21% 8% 34% 28% 9%	433
June	1st to 10th	Night	21% 7% 33% 30% 9% 2	400
	11th to 20th	Night	19% 7% 31% 34% 8% 1	400
	21st to end	Night	19% 6% 31% 35% 8%	400
July	1st to 10th	Night	16% 4 26% 43% 9% 2	390
	11th to 20th	Night	12% 5% 24% 44% 14% 1	388
	21st to end	Night	13% 4 28% 43% 11%	438
August	1st to 10th	Night	13% 3 26% 42% 15% 1	549
	11th to 20th	Night	13% 5% 27% 40% 15% 1	592
	21st to end	Night	13% 5% 25% 37% 18% 2	875
September	1st to 10th	Night	15% 5% 31% 34% 16% 1	800
	11th to 20th	Night	16% 6% 26% 29% 20% 4	800
	21st to end	Night	19% 7% 27% 31% 14% 2	800
October	1st to 10th	Night	22% 9% 27% 28% 13% 1	800
	11th to 20th	Night	18% 12% 31% 26% 11% 1	793
	21st to end	Night	24% 13% 33% 23% 6%	836
November	1st to 10th	Night	16% 12% 37% 26% 8% 1	780
	11th to 20th	Night	21% 18% 34% 20% 6% 1	800
	21st to end	Night	22% 21% 34% 18% 4 1	800
December	1st to 10th	Night	24% 16% 39% 17% 4	800
	11th to 20th	Night	23% 19% 34% 21% 3	800
	21st to end	Night	25% 18% 36% 20% 2	880

Page generated at 2025-10-16 01:50:25. Version ac07

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