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 2024-11-05.

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	10% 6% 2 6% 4 4 4 3 5% 7% 49%	105457
	Night	9% 6% 2 6% 3 3 4 3 5% 7% 51%	102195
Transparency	Day	35% 6% 13% 26% 18% 3	105214
	Night	32% 5% 13% 27% 20% 4	102029
Seeing	Day	13% 9% 31% 31% 13% 2	15782
	Night	12% 9% 36% 34% 9%	25657

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	6% 13% 5% 9% 6% 5% 4 4 5% 6% 37%	2538
	11th to 20th	Day	6% 11% 5% 9% 5% 4 5% 4 5% 7% 39%	2793
	21st to end	Day	7% 8% 4 14% 5% 4 4 2 4 5% 42%	3135
February	1st to 10th	Day	9% 11% 4 8% 5% 4 5% 4 6% 7% 39%	1710
	11th to 20th	Day	6% 8% 4 8% 4 4 4 4 6% 7% 45%	1820
	21st to end	Day	9% 8% 3 5% 4 4 4 4 5% 5% 49%	1570
March	1st to 10th	Day	10% 7% 2 5% 3 3 3 3 4 6% 54%	3240
	11th to 20th	Day	12% 7% 3 6% 3 3 3 3 4 5% 52%	3480
	21st to end	Day	17% 11% 3 8% 4 3 4 4 5% 7% 34%	3814
April	1st to 10th	Day	12% 7% 3 5% 4 3 3 3 5% 6% 47%	2152
	11th to 20th	Day	15% 8% 2 6% 4 4 3 3 5% 6% 44%	2396
	21st to end	Day	18% 7% 2 6% 4 4 4 3 5% 7% 40%	2470
May	1st to 10th	Day	14% 7% 2 5% 4 4 4 4 6% 7% 42%	4120
	11th to 20th	Day	14% 6% 2 6% 3 3 3 3 5% 6% 48%	4082
	21st to end	Day	14% 5% 3 7% 4 4 4 4 5% 7% 43%	4489
June	1st to 10th	Day	7% 4 2 4 4 4 4 4 6% 9% 54%	2482
	11th to 20th	Day	9% 5% 1 4 4 5% 4 4 5% 8% 50%	2660
	21st to end	Day	6% 4 1 4 4 4 5% 4 7% 9% 53%	2660
July	1st to 10th	Day	11% 5% 2 6% 4 4 4 3 6% 7% 47%	4430
	11th to 20th	Day	6% 4 2 5% 4 4 5% 4 7% 8% 51%	4275
	21st to end	Day	4 4 2 5% 4 4 4 4 6% 9% 54%	4466
August	1st to 10th	Day	7% 5% 2 6% 6% 5% 5% 4 6% 8% 46%	4103
	11th to 20th	Day	13% 7% 2 6% 4 4 4 4 6% 8% 43%	4041
	21st to end	Day	6% 4 2 6% 4 3 3 3 4 7% 57%	4450
September	1st to 10th	Day	12% 5% 2 5% 3 3 3 3 4 5% 55%	2139
	11th to 20th	Day	9% 4 1 5% 3 4 4 3 3 7% 57%	2090
	21st to end	Day	10% 4 1 4 3 2 3 3 4 6% 61%	2090
October	1st to 10th	Day	8% 4 1 3 2 2 2 2 3 4 70%	3391
	11th to 20th	Day	7% 3 1 3 2 2 3 3 4 6% 65%	3140
	21st to end	Day	10% 5% 2 4 3 3 3 3 5% 7% 55%	3255
November	1st to 10th	Day	8% 6% 2 4 3 4 4 4 5% 7% 54%	1709
	11th to 20th	Day	7% 7% 2 5% 4 3 2 4 4 6% 55%	1710
	21st to end	Day	10% 8% 2 5% 4 3 3 3 5% 6% 49%	1710
December	1st to 10th	Day	7% 6% 3 7% 3 5% 4 4 5% 7% 49%	1710
	11th to 20th	Day	7% 9% 3 7% 4 5% 4 3 6% 7% 46%	2161
	21st to end	Day	13% 11% 3 12% 5% 4 4 3 5% 5% 35%	2976
January	1st to 10th	Night	6% 13% 4 11% 5% 4 5% 4 6% 6% 36%	4417
	11th to 20th	Night	6% 9% 3 8% 4 4 6% 4 5% 5% 47%	4169
	21st to end	Night	7% 11% 5% 13% 4 3 4 4 5% 6% 39%	4532
February	1st to 10th	Night	8% 11% 4 8% 6% 4 4 4 5% 5% 42%	2470
	11th to 20th	Night	6% 8% 3 7% 5% 5% 5% 4 5% 7% 45%	2264
	21st to end	Night	7% 7% 2 6% 4 4 4 3 5% 6% 53%	1884
March	1st to 10th	Night	11% 6% 2 4 3 3 3 3 4 5% 57%	3618
	11th to 20th	Night	10% 6% 2 5% 3 3 2 2 5% 5% 58%	3480
	21st to end	Night	16% 8% 3 5% 3 3 4 4 6% 8% 39%	3817
April	1st to 10th	Night	12% 6% 2 6% 4 4 4 3 6% 7% 47%	2024
	11th to 20th	Night	12% 6% 2 5% 4 3 5% 3 6% 9% 44%	1732
	21st to end	Night	15% 5% 2 5% 4 3 3 3 5% 7% 48%	1710
May	1st to 10th	Night	19% 7% 1 4 4 3 4 3 4 6% 45%	2850
	11th to 20th	Night	10% 7% 2 6% 3 3 3 3 6% 9% 48%	2823
	21st to end	Night	14% 6% 3 6% 3 4 4 4 7% 8% 42%	3098
June	1st to 10th	Night	6% 4 1 4 3 4 4 4 7% 10% 53%	1691
	11th to 20th	Night	7% 5% 2 5% 3 3 3 3 6% 8% 54%	1520
	21st to end	Night	3 4 1 5% 4 4 4 4 6% 9% 57%	1520
July	1st to 10th	Night	9% 5% 2 5% 3 3 3 3 4 8% 55%	2540
	11th to 20th	Night	5% 3 1 4 3 4 3 5% 7% 10% 55%	2690
	21st to end	Night	3 3 1 3 3 3 3 4 6% 8% 62%	3097
August	1st to 10th	Night	4 3 2 4 3 4 5% 5% 7% 11% 52%	2836
	11th to 20th	Night	10% 5% 2 5% 4 3 4 4 5% 9% 48%	2798
	21st to end	Night	4 3 2 5% 3 4 4 3 6% 9% 57%	3199
September	1st to 10th	Night	8% 3 1 4 3 2 3 3 4 6% 63%	2040
	11th to 20th	Night	7% 4 2 4 4 3 3 3 5% 6% 59%	2090
	21st to end	Night	7% 3 2 4 3 3 3 4 5% 6% 60%	2090
October	1st to 10th	Night	9% 3 1 2 2 2 2 2 3 5% 70%	3536
	11th to 20th	Night	6% 3 1 4 3 2 2 2 4 6% 66%	3779
	21st to end	Night	9% 4 1 4 3 2 3 2 4 7% 58%	4295
November	1st to 10th	Night	5% 4 2 3 3 3 3 3 5% 7% 61%	2470
	11th to 20th	Night	8% 6% 2 5% 3 4 3 3 4 6% 56%	2470
	21st to end	Night	9% 6% 2 5% 2 3 3 3 5% 7% 54%	2470
December	1st to 10th	Night	6% 8% 2 6% 4 4 4 3 4 7% 51%	2470
	11th to 20th	Night	7% 6% 2 6% 4 3 3 3 5% 8% 52%	3036
	21st to end	Night	15% 11% 3 10% 4 3 3 2 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	46% 7% 13% 23% 9% 1	2539
	11th to 20th	Day	44% 6% 18% 18% 12% 2	2793
	21st to end	Day	45% 5% 13% 22% 13% 1	3135
February	1st to 10th	Day	44% 7% 15% 21% 10% 2	1710
	11th to 20th	Day	37% 5% 15% 23% 16% 4	1830
	21st to end	Day	36% 6% 12% 26% 16% 5%	1570
March	1st to 10th	Day	33% 5% 9% 25% 25% 3	3240
	11th to 20th	Day	35% 4 10% 29% 20% 1	3480
	21st to end	Day	48% 8% 22% 17% 5% 1	3814
April	1st to 10th	Day	37% 5% 14% 26% 16% 2	2152
	11th to 20th	Day	41% 5% 14% 22% 15% 3	2399
	21st to end	Day	43% 7% 11% 25% 13% 1	2470
May	1st to 10th	Day	38% 7% 13% 23% 15% 4	4120
	11th to 20th	Day	36% 7% 12% 28% 16% 1	4086
	21st to end	Day	40% 7% 11% 29% 12% 1	4489
June	1st to 10th	Day	26% 8% 18% 33% 14% 2	2482
	11th to 20th	Day	31% 6% 14% 28% 17% 3	2660
	21st to end	Day	26% 8% 15% 30% 17% 4	2660
July	1st to 10th	Day	35% 5% 11% 29% 18% 2	4361
	11th to 20th	Day	29% 8% 13% 29% 19% 3	4201
	21st to end	Day	24% 8% 15% 26% 22% 5%	4325
August	1st to 10th	Day	34% 8% 15% 25% 15% 4	4090
	11th to 20th	Day	38% 7% 14% 23% 16% 1	4080
	21st to end	Day	28% 6% 14% 24% 22% 7%	4449
September	1st to 10th	Day	32% 5% 11% 24% 21% 6%	2139
	11th to 20th	Day	28% 6% 11% 32% 22% 2	2090
	21st to end	Day	25% 4 9% 33% 27% 2	2090
October	1st to 10th	Day	21% 3 5% 21% 43% 7%	3391
	11th to 20th	Day	21% 4 10% 36% 21% 9%	3140
	21st to end	Day	30% 3 10% 31% 23% 3	3255
November	1st to 10th	Day	28% 4 14% 29% 21% 3	1709
	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	46% 6% 10% 24% 13% 1	4417
	11th to 20th	Night	38% 5% 14% 27% 15% 1	4169
	21st to end	Night	45% 6% 12% 20% 15% 1	4532
February	1st to 10th	Night	43% 5% 13% 23% 13% 3	2470
	11th to 20th	Night	37% 6% 13% 25% 15% 3	2264
	21st to end	Night	33% 4 12% 22% 22% 7%	1884
March	1st to 10th	Night	30% 3 8% 27% 25% 6%	3618
	11th to 20th	Night	29% 4 9% 28% 27% 4	3480
	21st to end	Night	42% 8% 21% 22% 7% 1	3817
April	1st to 10th	Night	36% 6% 14% 24% 19% 2	2024
	11th to 20th	Night	36% 7% 14% 26% 15% 3	1732
	21st to end	Night	36% 7% 12% 26% 18% 2	1710
May	1st to 10th	Night	40% 5% 11% 26% 16% 3	2850
	11th to 20th	Night	33% 8% 14% 26% 19% 1	2824
	21st to end	Night	37% 10% 14% 23% 14% 2	3099
June	1st to 10th	Night	24% 8% 19% 30% 17% 2	1691
	11th to 20th	Night	28% 6% 14% 28% 18% 6%	1520
	21st to end	Night	22% 6% 17% 31% 20% 3	1520
July	1st to 10th	Night	29% 5% 14% 32% 17% 3	2500
	11th to 20th	Night	23% 7% 14% 33% 19% 3	2642
	21st to end	Night	17% 7% 17% 28% 25% 6%	2999
August	1st to 10th	Night	24% 8% 18% 28% 18% 5%	2826
	11th to 20th	Night	33% 6% 17% 28% 15% 2	2825
	21st to end	Night	23% 6% 15% 29% 17% 9%	3199
September	1st to 10th	Night	23% 4 10% 28% 25% 9%	2040
	11th to 20th	Night	26% 4 11% 31% 24% 4	2090
	21st to end	Night	26% 5% 8% 28% 29% 4	2090
October	1st to 10th	Night	19% 3 6% 17% 46% 8%	3536
	11th to 20th	Night	21% 3 10% 29% 26% 10%	3779
	21st to end	Night	27% 3 10% 29% 27% 4	4295
November	1st to 10th	Night	22% 4 13% 29% 25% 6%	2470
	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	17% 16% 33% 26% 7% 1	270
	21st to end	Day	15% 8% 47% 23% 7% 1	297
February	1st to 10th	Day	13% 14% 45% 24% 4	270
	11th to 20th	Day	13% 10% 45% 24% 6% 1	270
	21st to end	Day	13% 18% 48% 16% 4	225
March	1st to 10th	Day	13% 14% 44% 25% 4 1	270
	11th to 20th	Day	21% 12% 36% 21% 9%	270
	21st to end	Day	27% 16% 37% 15% 4	297
April	1st to 10th	Day	18% 21% 39% 19% 3	332
	11th to 20th	Day	20% 15% 38% 23% 5%	597
	21st to end	Day	23% 16% 31% 20% 9% 2	650
May	1st to 10th	Day	17% 12% 34% 27% 9% 1	653
	11th to 20th	Day	20% 12% 29% 24% 12% 3	675
	21st to end	Day	16% 9% 30% 30% 12% 1	734
June	1st to 10th	Day	5% 6% 27% 35% 21% 4	680
	11th to 20th	Day	12% 6% 32% 33% 15% 3	680
	21st to end	Day	7% 7% 33% 34% 17% 2	680
July	1st to 10th	Day	9% 3 19% 38% 25% 5%	671
	11th to 20th	Day	5% 2 21% 45% 22% 5%	668
	21st to end	Day	8% 2 19% 41% 25% 4	739
August	1st to 10th	Day	7% 2 19% 46% 22% 4	676
	11th to 20th	Day	8% 5% 21% 42% 23% 2	665
	21st to end	Day	10% 3 22% 40% 21% 4	705
September	1st to 10th	Day	13% 4 28% 37% 15% 3	349
	11th to 20th	Day	6% 7% 29% 38% 14% 5%	300
	21st to end	Day	15% 8% 29% 28% 14% 6%	300
October	1st to 10th	Day	21% 7% 25% 32% 10% 4	300
	11th to 20th	Day	12% 13% 39% 25% 9% 1	300
	21st to end	Day	18% 16% 34% 24% 7% 1	330
November	1st to 10th	Day	15% 14% 40% 20% 9% 2	282
	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% 12% 40% 30% 6% 1	950
	21st to end	Night	12% 9% 42% 31% 6%	1045
February	1st to 10th	Night	13% 12% 42% 28% 5%	950
	11th to 20th	Night	11% 11% 42% 31% 5%	790
	21st to end	Night	11% 12% 46% 25% 6%	628
March	1st to 10th	Night	13% 13% 42% 29% 3	696
	11th to 20th	Night	16% 10% 41% 27% 5%	570
	21st to end	Night	20% 12% 40% 24% 4	627
April	1st to 10th	Night	17% 13% 43% 24% 2	570
	11th to 20th	Night	16% 14% 41% 25% 3 1	563
	21st to end	Night	19% 10% 34% 29% 7% 1	570
May	1st to 10th	Night	18% 9% 35% 31% 7%	570
	11th to 20th	Night	14% 9% 37% 32% 8% 1	561
	21st to end	Night	15% 7% 35% 31% 11% 1	617
June	1st to 10th	Night	7% 5% 27% 45% 14% 2	570
	11th to 20th	Night	8% 6% 38% 37% 11%	570
	21st to end	Night	4 4 35% 43% 14%	570
July	1st to 10th	Night	6% 3 21% 44% 25% 1	555
	11th to 20th	Night	3 2 21% 53% 21% 1	552
	21st to end	Night	5% 1 18% 55% 21%	624
August	1st to 10th	Night	5% 2 21% 49% 22% 2	567
	11th to 20th	Night	7% 2 25% 48% 18%	564
	21st to end	Night	7% 3 25% 43% 20% 2	627
September	1st to 10th	Night	9% 2 28% 43% 17% 1	570
	11th to 20th	Night	9% 4 34% 39% 14% 1	570
	21st to end	Night	8% 7% 36% 33% 15% 1	570
October	1st to 10th	Night	16% 8% 30% 33% 12%	600
	11th to 20th	Night	12% 11% 38% 31% 7%	760
	21st to end	Night	15% 12% 33% 30% 10%	936
November	1st to 10th	Night	8% 11% 37% 38% 6% 1	950
	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 2024-11-03 01:11:21. Version ac07

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