Pulpit Rock Astronomical Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pulpit Rock Astronomical 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 6% 7% 38%	126786
	Night	17% 7% 2 6% 4 4 4 3 5% 7% 41%	122927
Transparency	Day	43% 6% 12% 23% 15% 2	130331
	Night	41% 5% 11% 23% 16% 3	127456
Seeing	Day	22% 14% 27% 22% 11% 4	16134
	Night	21% 11% 27% 29% 11% 1	25394

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% 2 7% 5% 4 4 4 5% 6% 43%	3597
	11th to 20th	Day	13% 10% 5% 12% 5% 6% 4 3 5% 6% 31%	3728
	21st to end	Day	17% 10% 3 8% 5% 4 4 4 4 4 36%	4466
February	1st to 10th	Day	16% 8% 3 6% 6% 5% 5% 5% 5% 6% 35%	1800
	11th to 20th	Day	15% 9% 3 7% 5% 5% 3 4 6% 7% 36%	1850
	21st to end	Day	19% 10% 3 7% 5% 5% 4 3 4 5% 35%	1650
March	1st to 10th	Day	21% 5% 2 5% 4 5% 4 3 5% 5% 41%	4586
	11th to 20th	Day	12% 6% 3 7% 5% 4 4 3 5% 6% 43%	4980
	21st to end	Day	18% 7% 2 5% 4 4 4 4 5% 6% 42%	5728
April	1st to 10th	Day	18% 8% 3 7% 5% 4 5% 4 5% 6% 36%	2400
	11th to 20th	Day	17% 7% 2 7% 5% 4 4 4 5% 6% 39%	2374
	21st to end	Day	17% 6% 2 6% 5% 4 5% 4 6% 7% 39%	2400
May	1st to 10th	Day	28% 6% 2 6% 4 4 4 4 6% 7% 29%	5926
	11th to 20th	Day	25% 9% 3 6% 4 4 4 3 5% 7% 30%	6318
	21st to end	Day	20% 5% 2 5% 4 4 5% 4 7% 9% 35%	6949
June	1st to 10th	Day	13% 7% 2 6% 5% 6% 5% 4 7% 9% 37%	2800
	11th to 20th	Day	16% 6% 2 5% 5% 4 6% 5% 6% 9% 35%	2800
	21st to end	Day	12% 5% 1 6% 4 5% 6% 4 7% 10% 40%	2800
July	1st to 10th	Day	8% 6% 2 7% 6% 6% 5% 5% 7% 10% 38%	6360
	11th to 20th	Day	13% 7% 3 6% 6% 6% 5% 5% 7% 11% 32%	6360
	21st to end	Day	12% 7% 2 7% 5% 5% 5% 4 6% 8% 40%	6746
August	1st to 10th	Day	21% 5% 2 6% 5% 4 5% 5% 7% 8% 32%	4234
	11th to 20th	Day	15% 6% 2 6% 4 4 6% 4 6% 9% 39%	3944
	21st to end	Day	15% 5% 2 5% 3 3 3 3 6% 8% 46%	4312
September	1st to 10th	Day	17% 5% 2 6% 3 4 4 3 6% 6% 45%	2400
	11th to 20th	Day	12% 5% 2 4 3 3 4 3 5% 8% 51%	2400
	21st to end	Day	22% 7% 2 6% 4 4 4 3 5% 5% 38%	2145
October	1st to 10th	Day	19% 5% 2 5% 3 3 3 4 5% 7% 43%	2000
	11th to 20th	Day	17% 5% 2 5% 4 4 4 3 5% 6% 44%	1980
	21st to end	Day	20% 7% 2 5% 3 4 4 4 4 7% 41%	2051
November	1st to 10th	Day	14% 7% 2 4 3 3 2 2 4 7% 52%	1761
	11th to 20th	Day	17% 6% 2 5% 4 4 4 4 6% 6% 43%	1795
	21st to end	Day	18% 6% 2 5% 4 4 4 3 5% 8% 40%	1600
December	1st to 10th	Day	17% 9% 2 7% 4 4 4 4 5% 6% 39%	2600
	11th to 20th	Day	24% 9% 2 5% 3 3 3 3 4 6% 37%	2986
	21st to end	Day	19% 7% 3 7% 4 4 5% 3 6% 7% 34%	3960
January	1st to 10th	Night	13% 7% 2 7% 5% 4 4 3 5% 7% 43%	6349
	11th to 20th	Night	14% 7% 3 7% 5% 5% 4 4 6% 7% 39%	6155
	21st to end	Night	18% 7% 3 6% 4 4 4 3 5% 6% 40%	6490
February	1st to 10th	Night	17% 8% 3 6% 4 4 4 4 5% 7% 39%	2600
	11th to 20th	Night	17% 7% 2 7% 5% 5% 4 4 5% 6% 39%	2434
	21st to end	Night	18% 8% 2 6% 5% 4 3 3 6% 6% 39%	1980
March	1st to 10th	Night	18% 9% 2 6% 4 3 3 3 4 5% 41%	5236
	11th to 20th	Night	12% 6% 2 5% 4 4 4 3 4 6% 50%	4979
	21st to end	Night	16% 8% 2 7% 4 4 4 3 4 6% 42%	5202
April	1st to 10th	Night	19% 7% 2 7% 5% 4 4 4 5% 6% 37%	2000
	11th to 20th	Night	15% 7% 3 7% 5% 4 5% 4 5% 7% 40%	1975
	21st to end	Night	19% 4 2 5% 3 4 4 3 6% 6% 44%	2000
May	1st to 10th	Night	30% 7% 3 6% 4 4 4 3 5% 7% 29%	4058
	11th to 20th	Night	24% 9% 2 6% 4 4 4 3 5% 6% 32%	3575
	21st to end	Night	23% 6% 2 5% 4 4 4 3 5% 7% 37%	3926
June	1st to 10th	Night	17% 6% 3 6% 4 3 4 4 5% 8% 41%	1600
	11th to 20th	Night	14% 6% 1 6% 5% 4 5% 4 6% 8% 41%	1600
	21st to end	Night	12% 5% 2 5% 3 5% 4 4 7% 10% 44%	1600
July	1st to 10th	Night	11% 6% 3 7% 4 5% 5% 4 6% 10% 39%	3600
	11th to 20th	Night	16% 7% 3 8% 5% 5% 4 5% 6% 9% 32%	3600
	21st to end	Night	13% 6% 2 4 4 4 4 4 6% 8% 45%	4102
August	1st to 10th	Night	21% 6% 2 6% 4 4 5% 4 6% 7% 34%	2915
	11th to 20th	Night	16% 7% 2 7% 4 4 4 3 5% 6% 41%	3070
	21st to end	Night	14% 4 2 5% 3 3 4 4 5% 8% 48%	3586
September	1st to 10th	Night	16% 6% 2 6% 4 3 3 3 4 7% 48%	2000
	11th to 20th	Night	12% 6% 2 6% 3 4 3 3 4 6% 51%	2000
	21st to end	Night	21% 6% 2 5% 4 4 4 3 5% 5% 41%	2251
October	1st to 10th	Night	22% 5% 1 4 4 3 3 3 4 7% 44%	2400
	11th to 20th	Night	17% 6% 1 4 3 3 4 3 5% 6% 47%	2377
	21st to end	Night	20% 5% 2 4 3 3 3 3 5% 6% 45%	2546
November	1st to 10th	Night	12% 5% 2 5% 4 3 4 3 5% 6% 52%	2537
	11th to 20th	Night	16% 8% 3 6% 4 3 4 3 5% 5% 45%	2600
	21st to end	Night	15% 6% 2 6% 4 4 4 4 6% 7% 41%	2800
December	1st to 10th	Night	14% 8% 3 6% 4 4 4 3 5% 6% 42%	4580
	11th to 20th	Night	24% 7% 2 5% 3 3 4 3 4 6% 39%	5208
	21st to end	Night	20% 9% 3 6% 5% 4 4 3 4 6% 37%	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	38% 5% 11% 25% 19% 2	3598
	11th to 20th	Day	51% 5% 10% 18% 12% 4	3759
	21st to end	Day	49% 5% 12% 20% 12% 1	4466
February	1st to 10th	Day	47% 6% 14% 20% 12% 1	1800
	11th to 20th	Day	46% 5% 11% 24% 13% 2	1859
	21st to end	Day	50% 5% 11% 21% 11% 3	1650
March	1st to 10th	Day	42% 5% 10% 25% 12% 6%	4589
	11th to 20th	Day	39% 6% 12% 28% 10% 5%	4980
	21st to end	Day	42% 5% 11% 16% 21% 4	5728
April	1st to 10th	Day	46% 5% 10% 20% 14% 5%	2400
	11th to 20th	Day	43% 6% 10% 22% 15% 4	2374
	21st to end	Day	42% 6% 11% 22% 15% 5%	2400
May	1st to 10th	Day	52% 6% 13% 18% 9% 2	5935
	11th to 20th	Day	53% 6% 9% 21% 11% 1	6322
	21st to end	Day	43% 7% 12% 24% 13% 2	6949
June	1st to 10th	Day	40% 8% 14% 23% 14% 2	2800
	11th to 20th	Day	43% 8% 14% 23% 10% 2	2800
	21st to end	Day	38% 7% 15% 25% 15% 1	2800
July	1st to 10th	Day	39% 9% 13% 22% 15% 1	6290
	11th to 20th	Day	44% 8% 16% 21% 10% 1	6285
	21st to end	Day	40% 6% 11% 20% 22% 1	6551
August	1st to 10th	Day	48% 7% 12% 21% 10%	4221
	11th to 20th	Day	40% 7% 12% 29% 12% 1	3983
	21st to end	Day	35% 5% 11% 30% 17% 2	4312
September	1st to 10th	Day	40% 6% 10% 22% 20% 3	2400
	11th to 20th	Day	33% 5% 11% 25% 24% 3	2400
	21st to end	Day	48% 5% 8% 18% 19% 2	2145
October	1st to 10th	Day	38% 4 9% 21% 22% 5%	3260
	11th to 20th	Day	30% 4 11% 28% 22% 5%	3220
	21st to end	Day	27% 4 15% 25% 26% 3	3353
November	1st to 10th	Day	34% 4 14% 25% 20% 4	1761
	11th to 20th	Day	39% 5% 11% 25% 18% 2	1795
	21st to end	Day	42% 5% 13% 30% 9% 2	1600
December	1st to 10th	Day	45% 5% 16% 24% 9% 2	2600
	11th to 20th	Day	48% 4 14% 25% 8% 1	2986
	21st to end	Day	46% 6% 15% 20% 12% 1	3960
January	1st to 10th	Night	38% 6% 11% 24% 17% 3	6349
	11th to 20th	Night	40% 6% 14% 21% 14% 5%	6199
	21st to end	Night	43% 4 12% 22% 16% 2	6490
February	1st to 10th	Night	45% 5% 13% 26% 9% 2	2600
	11th to 20th	Night	45% 5% 11% 20% 16% 3	2436
	21st to end	Night	45% 5% 9% 21% 17% 4	1980
March	1st to 10th	Night	44% 5% 10% 22% 12% 7%	5246
	11th to 20th	Night	34% 6% 15% 27% 13% 5%	4980
	21st to end	Night	44% 4 7% 17% 23% 5%	5202
April	1st to 10th	Night	46% 5% 10% 22% 14% 3	2000
	11th to 20th	Night	42% 6% 11% 20% 20% 2	1975
	21st to end	Night	39% 6% 12% 21% 18% 5%	2000
May	1st to 10th	Night	55% 6% 10% 17% 10% 2	4065
	11th to 20th	Night	52% 8% 11% 17% 12% 1	3576
	21st to end	Night	47% 6% 10% 23% 12% 2	3927
June	1st to 10th	Night	40% 7% 10% 22% 19% 1	1600
	11th to 20th	Night	38% 8% 14% 25% 14% 1	1600
	21st to end	Night	35% 8% 14% 28% 14% 2	1600
July	1st to 10th	Night	42% 8% 13% 19% 15% 2	3560
	11th to 20th	Night	47% 7% 15% 20% 11% 1	3552
	21st to end	Night	35% 7% 13% 23% 21% 1	3982
August	1st to 10th	Night	47% 8% 16% 18% 10% 1	2904
	11th to 20th	Night	43% 5% 11% 24% 15% 1	3097
	21st to end	Night	34% 5% 11% 29% 19% 1	3586
September	1st to 10th	Night	37% 6% 10% 23% 21% 3	2000
	11th to 20th	Night	34% 5% 9% 25% 24% 3	2000
	21st to end	Night	44% 5% 9% 20% 21% 2	2251
October	1st to 10th	Night	41% 5% 9% 22% 21% 2	3920
	11th to 20th	Night	28% 4 8% 30% 25% 4	3876
	21st to end	Night	27% 4 12% 31% 23% 2	4182
November	1st to 10th	Night	33% 5% 14% 25% 19% 4	2537
	11th to 20th	Night	41% 4 9% 25% 17% 4	2600
	21st to end	Night	40% 5% 13% 28% 13% 2	2800
December	1st to 10th	Night	43% 5% 13% 29% 10% 1	4580
	11th to 20th	Night	47% 4 11% 24% 12% 2	5208
	21st to end	Night	48% 5% 11% 20% 15% 1	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% 29% 25% 15% 4 1	200
	11th to 20th	Day	32% 27% 29% 9% 2	235
	21st to end	Day	24% 27% 31% 13% 4 1	330
February	1st to 10th	Day	25% 27% 30% 14% 3	300
	11th to 20th	Day	30% 22% 34% 13% 1	397
	21st to end	Day	30% 17% 30% 21% 2	414
March	1st to 10th	Day	26% 21% 31% 19% 3	500
	11th to 20th	Day	23% 26% 31% 15% 4 1	500
	21st to end	Day	28% 22% 29% 15% 4 1	550
April	1st to 10th	Day	27% 20% 30% 16% 5% 2	500
	11th to 20th	Day	24% 24% 27% 15% 8% 2	492
	21st to end	Day	26% 17% 30% 18% 5% 3	500
May	1st to 10th	Day	30% 16% 25% 18% 8% 3	503
	11th to 20th	Day	24% 14% 32% 20% 8% 2	527
	21st to end	Day	22% 7% 27% 24% 16% 5%	573
June	1st to 10th	Day	15% 15% 30% 24% 13% 4	530
	11th to 20th	Day	22% 10% 30% 22% 14% 3	530
	21st to end	Day	16% 10% 30% 27% 12% 4	530
July	1st to 10th	Day	14% 4 25% 30% 19% 8%	525
	11th to 20th	Day	10% 5% 27% 31% 22% 5%	524
	21st to end	Day	13% 6% 29% 33% 15% 4	576
August	1st to 10th	Day	13% 4 24% 29% 21% 9%	526
	11th to 20th	Day	15% 5% 20% 34% 19% 7%	519
	21st to end	Day	15% 5% 26% 29% 16% 10%	583
September	1st to 10th	Day	19% 10% 19% 24% 21% 7%	530
	11th to 20th	Day	12% 5% 21% 32% 20% 10%	530
	21st to end	Day	28% 10% 22% 21% 15% 4	530
October	1st to 10th	Day	24% 7% 22% 24% 15% 7%	530
	11th to 20th	Day	21% 13% 29% 22% 13% 2	522
	21st to end	Day	23% 13% 29% 22% 12% 1	518
November	1st to 10th	Day	18% 15% 25% 27% 12% 3	395
	11th to 20th	Day	21% 17% 31% 24% 7%	395
	21st to end	Day	25% 24% 30% 17% 4 1	200
December	1st to 10th	Day	30% 22% 29% 13% 7% 1	200
	11th to 20th	Day	30% 26% 26% 15% 4	200
	21st to end	Day	27% 20% 29% 17% 4 2	220
January	1st to 10th	Night	21% 17% 39% 21% 3	800
	11th to 20th	Night	26% 16% 28% 26% 4	800
	21st to end	Night	18% 17% 36% 25% 3	880
February	1st to 10th	Night	23% 16% 32% 28% 2	800
	11th to 20th	Night	24% 19% 37% 18% 2	783
	21st to end	Night	25% 17% 35% 21% 2	660
March	1st to 10th	Night	24% 18% 31% 23% 4	800
	11th to 20th	Night	25% 16% 32% 22% 5% 1	800
	21st to end	Night	23% 16% 34% 22% 4 1	880
April	1st to 10th	Night	25% 17% 32% 22% 5%	800
	11th to 20th	Night	19% 15% 35% 24% 7%	791
	21st to end	Night	23% 12% 29% 28% 7%	800
May	1st to 10th	Night	25% 10% 27% 29% 9%	605
	11th to 20th	Night	21% 8% 28% 32% 10% 1	394
	21st to end	Night	20% 7% 19% 38% 14% 2	433
June	1st to 10th	Night	17% 7% 21% 37% 19%	400
	11th to 20th	Night	18% 4 26% 39% 14% 1	400
	21st to end	Night	13% 5% 22% 45% 16% 1	400
July	1st to 10th	Night	12% 3 19% 40% 23% 3	390
	11th to 20th	Night	12% 3 19% 39% 26% 2	388
	21st to end	Night	11% 4 16% 44% 24% 1	513
August	1st to 10th	Night	15% 2 13% 40% 28% 2	597
	11th to 20th	Night	15% 3 15% 34% 30% 2	711
	21st to end	Night	17% 2 17% 35% 27% 3	880
September	1st to 10th	Night	18% 4 20% 36% 20% 3	800
	11th to 20th	Night	14% 5% 14% 38% 24% 5%	800
	21st to end	Night	23% 4 18% 33% 19% 2	800
October	1st to 10th	Night	24% 7% 21% 27% 18% 4	800
	11th to 20th	Night	21% 10% 23% 34% 12% 1	793
	21st to end	Night	24% 9% 27% 29% 10%	836
November	1st to 10th	Night	16% 10% 31% 30% 12% 1	780
	11th to 20th	Night	20% 15% 28% 28% 8% 1	800
	21st to end	Night	18% 16% 29% 31% 6%	800
December	1st to 10th	Night	26% 14% 32% 23% 5% 1	800
	11th to 20th	Night	23% 12% 32% 28% 5%	800
	21st to end	Night	25% 10% 31% 30% 3	880

Page generated at 2025-10-16 01:50:24. Version ac07

Copyright © 2025 Attilla Danko.