Prairie Golf Association
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Prairie Golf Association clear sky chart from 2005-11-06 to 2024-01-12.

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	10% 6% 3 5% 5% 3 4 4 5% 7% 48%	75146
	Night	9% 6% 2 5% 4 3 4 4 5% 7% 51%	74549
Transparency	Day	35% 6% 14% 26% 16% 3	74864
	Night	33% 6% 13% 27% 18% 3	74355
Seeing	Day	13% 9% 31% 31% 14% 2	14601
	Night	12% 9% 36% 34% 9%	24634

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	8% 10% 4 5% 5% 3 4 4 4 6% 48%	1518
	11th to 20th	Day	8% 8% 3 6% 5% 3 4 5% 5% 7% 45%	1597
	21st to end	Day	8% 9% 3 9% 7% 4 5% 3 4 6% 41%	1782
February	1st to 10th	Day	8% 10% 5% 7% 6% 3 4 5% 5% 7% 40%	1620
	11th to 20th	Day	7% 8% 4 7% 4 3 5% 4 5% 8% 44%	1722
	21st to end	Day	9% 8% 3 5% 5% 4 4 4 5% 5% 47%	1480
March	1st to 10th	Day	9% 6% 3 5% 4 3 4 4 4 8% 50%	1858
	11th to 20th	Day	14% 8% 2 5% 4 3 4 4 5% 6% 44%	1980
	21st to end	Day	15% 11% 4 6% 5% 3 4 4 4 7% 35%	2178
April	1st to 10th	Day	12% 7% 3 5% 5% 3 3 4 5% 7% 47%	2038
	11th to 20th	Day	15% 8% 3 5% 4 2 4 3 5% 7% 44%	2268
	21st to end	Day	19% 6% 2 5% 5% 3 4 4 4 7% 41%	2340
May	1st to 10th	Day	15% 6% 3 5% 5% 2 5% 5% 6% 7% 41%	2340
	11th to 20th	Day	16% 6% 2 5% 5% 3 4 4 5% 7% 43%	2302
	21st to end	Day	14% 5% 4 6% 6% 4 5% 5% 6% 8% 38%	2531
June	1st to 10th	Day	7% 3 2 3 5% 3 4 5% 6% 9% 54%	2351
	11th to 20th	Day	9% 5% 1 4 4 3 5% 5% 5% 8% 51%	2520
	21st to end	Day	6% 3 2 3 4 3 4 5% 6% 10% 53%	2520
July	1st to 10th	Day	8% 4 2 4 5% 3 4 4 6% 9% 51%	2520
	11th to 20th	Day	6% 3 1 3 4 3 5% 5% 6% 8% 57%	2430
	21st to end	Day	7% 3 3 4 5% 3 5% 5% 6% 9% 51%	2546
August	1st to 10th	Day	7% 5% 2 5% 7% 3 5% 6% 7% 9% 45%	2328
	11th to 20th	Day	8% 4 1 4 4 2 3 4 6% 8% 55%	2301
	21st to end	Day	8% 5% 2 4 5% 2 4 3 5% 7% 55%	2534
September	1st to 10th	Day	13% 4 2 4 4 2 3 3 4 5% 55%	2027
	11th to 20th	Day	10% 4 1 4 4 3 3 4 3 7% 57%	1980
	21st to end	Day	10% 4 2 3 4 1 3 4 4 6% 60%	1980
October	1st to 10th	Day	14% 6% 2 4 3 2 3 3 4 5% 53%	1933
	11th to 20th	Day	11% 4 2 4 4 2 3 3 4 6% 58%	1800
	21st to end	Day	14% 7% 3 4 3 2 2 3 4 5% 53%	1882
November	1st to 10th	Day	7% 5% 2 4 3 3 4 5% 5% 7% 56%	1673
	11th to 20th	Day	7% 6% 2 5% 5% 2 3 4 4 6% 55%	1710
	21st to end	Day	11% 8% 2 4 4 2 4 4 5% 7% 49%	1710
December	1st to 10th	Day	8% 6% 3 6% 4 4 4 5% 5% 7% 49%	1710
	11th to 20th	Day	7% 8% 3 7% 5% 3 5% 4 5% 7% 46%	2161
	21st to end	Day	13% 10% 4 11% 5% 3 4 4 5% 5% 35%	2976
January	1st to 10th	Night	6% 9% 3 6% 4 3 5% 4 5% 7% 47%	2647
	11th to 20th	Night	7% 8% 4 7% 5% 3 4 4 5% 6% 47%	2378
	21st to end	Night	7% 10% 3 7% 5% 3 4 4 5% 7% 45%	2574
February	1st to 10th	Night	8% 10% 4 7% 6% 2 4 5% 5% 6% 43%	2340
	11th to 20th	Night	6% 7% 4 6% 6% 4 6% 5% 5% 7% 45%	2141
	21st to end	Night	8% 7% 3 6% 4 3 4 4 5% 6% 51%	1776
March	1st to 10th	Night	10% 7% 3 4 4 2 4 4 5% 6% 51%	2100
	11th to 20th	Night	14% 7% 3 4 3 3 3 3 5% 6% 50%	1980
	21st to end	Night	15% 9% 4 5% 4 3 5% 4 5% 7% 40%	2178
April	1st to 10th	Night	13% 5% 2 5% 5% 3 4 4 6% 7% 47%	1918
	11th to 20th	Night	12% 6% 3 5% 4 2 5% 4 5% 10% 44%	1640
	21st to end	Night	15% 5% 2 5% 4 3 3 4 5% 7% 48%	1620
May	1st to 10th	Night	14% 6% 2 4 4 3 5% 4 5% 8% 44%	1620
	11th to 20th	Night	13% 7% 2 4 5% 3 3 3 6% 9% 45%	1593
	21st to end	Night	13% 6% 2 5% 4 2 5% 4 7% 9% 43%	1745
June	1st to 10th	Night	6% 4 1 3 3 3 4 5% 6% 10% 54%	1602
	11th to 20th	Night	7% 4 2 5% 4 1 4 4 6% 7% 55%	1440
	21st to end	Night	3 3 2 4 4 3 4 4 6% 10% 57%	1440
July	1st to 10th	Night	6% 4 2 5% 4 2 4 5% 5% 10% 53%	1440
	11th to 20th	Night	3 2 1 3 3 3 4 5% 6% 8% 61%	1525
	21st to end	Night	4 3 2 3 4 3 4 6% 7% 9% 55%	1772
August	1st to 10th	Night	5% 3 2 5% 4 3 5% 7% 6% 9% 50%	1611
	11th to 20th	Night	6% 3 1 4 4 3 4 5% 5% 10% 55%	1600
	21st to end	Night	6% 4 2 4 3 2 4 4 5% 5% 62%	1818
September	1st to 10th	Night	9% 3 1 3 3 2 3 4 4 6% 62%	1932
	11th to 20th	Night	8% 4 2 4 4 2 3 3 5% 6% 59%	1980
	21st to end	Night	8% 3 2 3 4 3 3 4 4 6% 60%	1980
October	1st to 10th	Night	15% 4 1 3 4 2 3 3 4 7% 52%	2008
	11th to 20th	Night	11% 5% 2 4 3 1 3 3 4 5% 59%	2160
	21st to end	Night	13% 5% 2 3 4 2 3 3 4 7% 56%	2470
November	1st to 10th	Night	4 4 2 3 3 2 3 4 5% 7% 62%	2405
	11th to 20th	Night	8% 6% 2 4 4 3 4 4 4 6% 57%	2470
	21st to end	Night	9% 5% 2 4 3 2 3 4 5% 8% 54%	2470
December	1st to 10th	Night	6% 7% 3 5% 5% 3 4 4 4 7% 51%	2470
	11th to 20th	Night	7% 6% 2 5% 5% 2 4 4 5% 8% 52%	3036
	21st to end	Night	15% 11% 4 9% 5% 2 3 3 4 6% 38%	4670

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% 4 15% 27% 14% 2	1519
	11th to 20th	Day	37% 7% 15% 24% 14% 2	1597
	21st to end	Day	44% 6% 14% 22% 11% 2	1782
February	1st to 10th	Day	43% 7% 15% 22% 11% 2	1620
	11th to 20th	Day	38% 5% 14% 23% 15% 4	1732
	21st to end	Day	38% 6% 13% 25% 14% 4	1480
March	1st to 10th	Day	34% 6% 13% 26% 18% 3	1858
	11th to 20th	Day	41% 5% 11% 26% 15% 2	1980
	21st to end	Day	50% 5% 15% 20% 9% 1	2178
April	1st to 10th	Day	38% 5% 15% 26% 14% 2	2038
	11th to 20th	Day	41% 5% 14% 23% 14% 3	2271
	21st to end	Day	43% 6% 11% 25% 13% 1	2340
May	1st to 10th	Day	41% 8% 15% 20% 15% 1	2340
	11th to 20th	Day	41% 7% 16% 24% 13%	2306
	21st to end	Day	44% 8% 15% 21% 10% 1	2531
June	1st to 10th	Day	26% 8% 18% 33% 14% 2	2351
	11th to 20th	Day	31% 6% 14% 28% 18% 3	2520
	21st to end	Day	26% 8% 15% 30% 17% 4	2520
July	1st to 10th	Day	29% 6% 15% 30% 17% 2	2451
	11th to 20th	Day	25% 8% 13% 29% 21% 5%	2356
	21st to end	Day	28% 8% 16% 32% 16% 1	2405
August	1st to 10th	Day	32% 10% 18% 27% 12% 1	2314
	11th to 20th	Day	27% 6% 14% 33% 18% 1	2301
	21st to end	Day	29% 5% 13% 23% 24% 5%	2534
September	1st to 10th	Day	33% 5% 12% 24% 20% 7%	2027
	11th to 20th	Day	28% 5% 11% 31% 22% 2	1980
	21st to end	Day	25% 4 10% 33% 26% 1	1980
October	1st to 10th	Day	35% 4 9% 26% 25% 2	1933
	11th to 20th	Day	29% 3 9% 30% 21% 8%	1800
	21st to end	Day	35% 3 12% 24% 22% 4	1882
November	1st to 10th	Day	27% 4 14% 30% 22% 3	1673
	11th to 20th	Day	31% 4 11% 28% 23% 3	1710
	21st to end	Day	36% 4 12% 26% 18% 4	1710
December	1st to 10th	Day	35% 5% 15% 28% 14% 3	1710
	11th to 20th	Day	37% 5% 14% 30% 13%	2159
	21st to end	Day	51% 5% 10% 21% 11% 1	2976
January	1st to 10th	Night	37% 6% 11% 28% 17% 1	2647
	11th to 20th	Night	38% 5% 13% 28% 14% 1	2378
	21st to end	Night	38% 6% 16% 25% 13% 2	2574
February	1st to 10th	Night	43% 5% 13% 22% 13% 3	2340
	11th to 20th	Night	38% 6% 14% 25% 14% 3	2141
	21st to end	Night	34% 4 12% 23% 21% 6%	1776
March	1st to 10th	Night	35% 4 10% 29% 18% 4	2100
	11th to 20th	Night	36% 4 10% 25% 21% 4	1980
	21st to end	Night	44% 6% 14% 23% 11% 2	2178
April	1st to 10th	Night	36% 6% 14% 24% 18% 2	1918
	11th to 20th	Night	37% 7% 14% 27% 14% 2	1640
	21st to end	Night	36% 7% 12% 26% 18% 2	1620
May	1st to 10th	Night	38% 6% 14% 24% 15% 1	1620
	11th to 20th	Night	37% 7% 16% 25% 15%	1594
	21st to end	Night	36% 10% 16% 23% 12% 2	1746
June	1st to 10th	Night	25% 8% 19% 31% 16% 2	1602
	11th to 20th	Night	27% 6% 15% 28% 18% 6%	1440
	21st to end	Night	23% 6% 16% 31% 20% 4	1440
July	1st to 10th	Night	26% 7% 15% 27% 20% 4	1400
	11th to 20th	Night	20% 8% 15% 29% 23% 5%	1477
	21st to end	Night	22% 7% 17% 34% 17% 3	1673
August	1st to 10th	Night	27% 11% 19% 28% 12% 3	1601
	11th to 20th	Night	24% 6% 15% 33% 19% 2	1600
	21st to end	Night	24% 6% 11% 27% 23% 8%	1818
September	1st to 10th	Night	24% 4 11% 27% 24% 10%	1932
	11th to 20th	Night	26% 4 10% 31% 25% 4	1980
	21st to end	Night	26% 5% 9% 28% 29% 3	1980
October	1st to 10th	Night	33% 5% 11% 25% 24% 3	2008
	11th to 20th	Night	28% 4 8% 26% 27% 7%	2160
	21st to end	Night	30% 4 11% 26% 23% 6%	2470
November	1st to 10th	Night	21% 4 13% 29% 26% 6%	2405
	11th to 20th	Night	29% 4 10% 29% 23% 5%	2470
	21st to end	Night	30% 4 13% 27% 22% 4	2470
December	1st to 10th	Night	32% 5% 14% 30% 17% 2	2470
	11th to 20th	Night	31% 4 13% 37% 15% 1	3037
	21st to end	Night	48% 5% 11% 25% 10% 1	4670

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	16% 14% 37% 23% 9% 1	270
	11th to 20th	Day	18% 13% 33% 27% 8% 1	243
	21st to end	Day	16% 8% 50% 20% 5%	264
February	1st to 10th	Day	11% 15% 45% 25% 3	240
	11th to 20th	Day	14% 11% 45% 24% 5% 2	240
	21st to end	Day	14% 18% 46% 17% 5% 1	198
March	1st to 10th	Day	13% 13% 45% 25% 5% 1	240
	11th to 20th	Day	22% 11% 37% 21% 9%	240
	21st to end	Day	26% 17% 36% 15% 5%	264
April	1st to 10th	Day	16% 20% 40% 19% 3	298
	11th to 20th	Day	20% 14% 38% 23% 5%	549
	21st to end	Day	23% 15% 31% 20% 9% 2	600
May	1st to 10th	Day	17% 12% 33% 28% 10% 1	603
	11th to 20th	Day	20% 11% 30% 23% 12% 3	625
	21st to end	Day	17% 9% 29% 31% 13% 1	679
June	1st to 10th	Day	6% 6% 27% 35% 22% 5%	630
	11th to 20th	Day	11% 6% 32% 33% 16% 3	630
	21st to end	Day	7% 7% 31% 34% 18% 2	630
July	1st to 10th	Day	8% 3 18% 39% 26% 5%	621
	11th to 20th	Day	5% 2 20% 45% 22% 5%	618
	21st to end	Day	8% 2 20% 42% 25% 4	684
August	1st to 10th	Day	7% 2 19% 46% 22% 4	626
	11th to 20th	Day	7% 4 20% 42% 25% 2	615
	21st to end	Day	10% 2 23% 39% 21% 4	653
September	1st to 10th	Day	14% 4 29% 36% 15% 3	317
	11th to 20th	Day	7% 7% 28% 39% 14% 6%	270
	21st to end	Day	15% 8% 31% 29% 14% 3	270
October	1st to 10th	Day	23% 7% 25% 31% 9% 4	270
	11th to 20th	Day	14% 13% 38% 24% 9% 1	270
	21st to end	Day	18% 18% 34% 23% 7% 1	297
November	1st to 10th	Day	13% 14% 40% 21% 9% 2	270
	11th to 20th	Day	11% 15% 46% 21% 7%	270
	21st to end	Day	21% 14% 33% 21% 9% 1	270
December	1st to 10th	Day	9% 11% 43% 31% 4 1	270
	11th to 20th	Day	16% 9% 41% 28% 6%	270
	21st to end	Day	19% 12% 44% 23% 2	297
January	1st to 10th	Night	11% 12% 36% 33% 6% 1	950
	11th to 20th	Night	12% 11% 40% 30% 6% 1	906
	21st to end	Night	12% 9% 43% 30% 6%	990
February	1st to 10th	Night	13% 12% 43% 27% 4	900
	11th to 20th	Night	12% 11% 43% 29% 5%	747
	21st to end	Night	11% 13% 44% 26% 6%	592
March	1st to 10th	Night	13% 13% 42% 28% 3	660
	11th to 20th	Night	17% 10% 40% 28% 5%	540
	21st to end	Night	20% 12% 40% 24% 4	594
April	1st to 10th	Night	17% 12% 44% 24% 2	540
	11th to 20th	Night	16% 14% 40% 26% 3 1	533
	21st to end	Night	19% 10% 32% 30% 7% 1	540
May	1st to 10th	Night	17% 9% 34% 32% 7%	540
	11th to 20th	Night	15% 9% 36% 32% 8% 1	531
	21st to end	Night	15% 8% 33% 32% 12% 1	584
June	1st to 10th	Night	7% 5% 26% 45% 14% 2	540
	11th to 20th	Night	8% 6% 37% 38% 11%	540
	21st to end	Night	4 4 34% 44% 14%	540
July	1st to 10th	Night	6% 2 21% 44% 26% 1	525
	11th to 20th	Night	3 2 21% 52% 21% 1	522
	21st to end	Night	5% 2 18% 56% 20%	591
August	1st to 10th	Night	5% 2 20% 49% 22% 2	537
	11th to 20th	Night	7% 1 25% 48% 19%	534
	21st to end	Night	7% 3 24% 44% 20% 2	594
September	1st to 10th	Night	9% 3 28% 42% 16% 1	540
	11th to 20th	Night	10% 4 34% 38% 14% 1	540
	21st to end	Night	8% 7% 37% 34% 13% 1	540
October	1st to 10th	Night	17% 8% 31% 32% 12%	568
	11th to 20th	Night	13% 12% 38% 30% 8%	720
	21st to end	Night	15% 11% 32% 30% 11%	886
November	1st to 10th	Night	7% 11% 37% 38% 6% 1	925
	11th to 20th	Night	11% 11% 41% 31% 7%	950
	21st to end	Night	12% 10% 37% 31% 10%	950
December	1st to 10th	Night	11% 11% 44% 29% 4	950
	11th to 20th	Night	13% 9% 41% 31% 6%	950
	21st to end	Night	17% 11% 38% 28% 5%	1045

Page generated at 2024-01-08 21:31:27. Version ac07

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