High Prairie
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the High Prairie clear sky chart from 2005-11-06 to 2024-11-02.

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	9% 8% 3 6% 4 4 4 4 5% 6% 47%	101544
	Night	11% 9% 3 7% 5% 4 4 4 5% 6% 42%	97589
Transparency	Day	36% 5% 13% 23% 15% 8%	101287
	Night	41% 6% 14% 22% 12% 5%	97435
Seeing	Day	16% 15% 27% 23% 14% 5%	14519
	Night	15% 10% 24% 32% 17% 2	23490

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	21% 21% 6% 13% 8% 6% 6% 3 4 3 8%	2539
	11th to 20th	Day	23% 19% 5% 11% 5% 6% 5% 3 5% 5% 12%	2540
	21st to end	Day	31% 17% 6% 14% 7% 5% 3 3 3 3 8%	2893
February	1st to 10th	Day	16% 15% 4 9% 6% 5% 6% 6% 6% 6% 21%	1710
	11th to 20th	Day	15% 11% 4 7% 6% 6% 7% 4 7% 7% 26%	1665
	21st to end	Day	10% 11% 4 10% 8% 6% 6% 5% 7% 7% 25%	1554
March	1st to 10th	Day	9% 11% 4 8% 7% 6% 8% 6% 8% 9% 25%	3138
	11th to 20th	Day	9% 7% 3 7% 5% 4 4 4 6% 6% 45%	3489
	21st to end	Day	10% 10% 4 10% 7% 6% 6% 6% 7% 8% 26%	4009
April	1st to 10th	Day	10% 9% 3 8% 6% 6% 6% 6% 8% 8% 31%	2280
	11th to 20th	Day	8% 8% 3 7% 6% 6% 7% 5% 6% 7% 37%	2249
	21st to end	Day	5% 5% 2 7% 4 5% 6% 5% 8% 9% 42%	2427
May	1st to 10th	Day	9% 5% 2 6% 4 4 5% 4 6% 6% 48%	4420
	11th to 20th	Day	5% 4 1 3 3 3 2 3 5% 7% 64%	4377
	21st to end	Day	7% 6% 2 7% 5% 5% 6% 5% 7% 8% 42%	4813
June	1st to 10th	Day	7% 7% 3 6% 4 5% 4 4 7% 8% 46%	2660
	11th to 20th	Day	4 4 2 5% 5% 5% 4 4 6% 9% 52%	2660
	21st to end	Day	3 3 1 3 3 3 3 3 5% 6% 66%	2660
July	1st to 10th	Day	1 1 1 1 1 1 2 3 3 84%	4420
	11th to 20th	Day	1 1 1 1 1 1 2 2 3 84%	4420
	21st to end	Day	2 1 1 2 1 2 2 1 3 4 82%	4790
August	1st to 10th	Day	2 3 1 3 2 2 2 2 4 4 75%	4318
	11th to 20th	Day	1 2 1 3 2 3 4 3 5% 7% 71%	4026
	21st to end	Day	4 4 2 4 3 3 3 2 4 5% 67%	4194
September	1st to 10th	Day	2 1 1 2 2 2 3 2 4 6% 74%	2280
	11th to 20th	Day	4 3 2 5% 4 4 5% 4 5% 7% 59%	2280
	21st to end	Day	7% 4 2 6% 4 4 4 3 4 6% 57%	2034
October	1st to 10th	Day	8% 6% 2 5% 5% 3 5% 4 6% 7% 49%	1900
	11th to 20th	Day	9% 5% 3 8% 5% 5% 6% 4 7% 7% 40%	1900
	21st to end	Day	14% 9% 2 8% 6% 6% 5% 4 5% 7% 34%	1962
November	1st to 10th	Day	16% 11% 4 9% 6% 6% 6% 4 7% 7% 24%	1655
	11th to 20th	Day	16% 16% 4 11% 7% 7% 5% 4 6% 7% 17%	1520
	21st to end	Day	17% 12% 3 10% 7% 6% 6% 5% 6% 6% 22%	1520
December	1st to 10th	Day	15% 17% 6% 12% 7% 4 4 3 5% 5% 22%	1520
	11th to 20th	Day	21% 20% 8% 16% 7% 4 4 3 4 4 9%	1928
	21st to end	Day	22% 21% 8% 14% 7% 5% 4 2 4 3 10%	2794
January	1st to 10th	Night	21% 21% 6% 12% 6% 5% 5% 4 5% 4 11%	4406
	11th to 20th	Night	26% 17% 5% 10% 5% 4 4 3 4 6% 17%	4420
	21st to end	Night	29% 16% 6% 13% 6% 4 4 2 4 4 12%	4765
February	1st to 10th	Night	16% 15% 4 8% 5% 5% 5% 4 6% 7% 26%	2470
	11th to 20th	Night	14% 11% 3 8% 6% 5% 5% 3 6% 7% 33%	2402
	21st to end	Night	11% 13% 3 9% 7% 6% 5% 4 6% 8% 28%	1899
March	1st to 10th	Night	9% 10% 4 9% 6% 6% 7% 5% 7% 9% 28%	3736
	11th to 20th	Night	7% 6% 2 6% 5% 4 4 4 5% 6% 51%	3490
	21st to end	Night	10% 8% 3 8% 8% 7% 7% 5% 7% 9% 27%	3643
April	1st to 10th	Night	11% 8% 3 7% 6% 5% 5% 6% 6% 9% 35%	1900
	11th to 20th	Night	8% 6% 2 6% 5% 5% 5% 4 6% 7% 45%	1879
	21st to end	Night	7% 5% 2 5% 4 4 5% 5% 9% 9% 45%	1752
May	1st to 10th	Night	10% 8% 2 5% 4 3 3 3 4 6% 51%	2540
	11th to 20th	Night	4 3 1 3 3 3 3 3 6% 7% 65%	2516
	21st to end	Night	3 4 1 5% 5% 5% 5% 5% 7% 10% 50%	2762
June	1st to 10th	Night	8% 6% 2 6% 4 5% 5% 5% 6% 7% 46%	1520
	11th to 20th	Night	5% 4 1 4 4 3 4 3 5% 9% 58%	1520
	21st to end	Night	2 3 1 3 3 4 4 3 5% 5% 68%	1520
July	1st to 10th	Night	1 1 1 1 1 1 2 2 3 86%	2540
	11th to 20th	Night	1 1 1 2 2 1 2 3 4 83%	2540
	21st to end	Night	1 1 1 1 1 2 1 2 4 86%	2761
August	1st to 10th	Night	3 2 1 2 2 2 2 2 3 5% 75%	2612
	11th to 20th	Night	2 2 1 3 2 3 3 3 5% 5% 73%	2812
	21st to end	Night	2 3 1 2 3 2 3 2 4 5% 72%	3484
September	1st to 10th	Night	1 2 1 3 2 2 2 3 3 5% 76%	1900
	11th to 20th	Night	4 3 2 4 3 4 5% 3 4 5% 63%	1900
	21st to end	Night	6% 3 1 4 3 4 4 3 5% 6% 60%	2142
October	1st to 10th	Night	8% 6% 2 6% 3 4 3 3 5% 7% 55%	2280
	11th to 20th	Night	10% 6% 2 6% 5% 5% 5% 4 5% 7% 47%	2280
	21st to end	Night	13% 7% 3 7% 4 4 4 4 6% 6% 43%	2636
November	1st to 10th	Night	17% 8% 4 8% 4 5% 6% 5% 7% 6% 31%	2444
	11th to 20th	Night	17% 12% 4 9% 7% 5% 6% 4 5% 5% 25%	2660
	21st to end	Night	14% 10% 3 9% 6% 6% 6% 5% 5% 7% 29%	2660
December	1st to 10th	Night	18% 15% 5% 11% 6% 5% 5% 3 4 5% 24%	2660
	11th to 20th	Night	23% 16% 5% 15% 7% 7% 5% 4 4 4 10%	3276
	21st to end	Night	21% 19% 6% 11% 5% 4 5% 3 5% 4 17%	4862

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	73% 6% 10% 11%	2539
	11th to 20th	Day	72% 4 16% 7% 1	2540
	21st to end	Day	80% 5% 7% 6% 2	2893
February	1st to 10th	Day	61% 9% 17% 11% 2	1710
	11th to 20th	Day	52% 9% 18% 17% 4	1674
	21st to end	Day	51% 10% 17% 14% 8%	1554
March	1st to 10th	Day	50% 10% 12% 21% 7%	3138
	11th to 20th	Day	37% 6% 18% 33% 7%	3489
	21st to end	Day	51% 7% 16% 21% 5%	4009
April	1st to 10th	Day	44% 9% 18% 20% 8%	2280
	11th to 20th	Day	41% 7% 19% 19% 11% 3	2252
	21st to end	Day	33% 8% 20% 25% 12% 2	2427
May	1st to 10th	Day	33% 5% 12% 28% 20% 2	4420
	11th to 20th	Day	20% 3 12% 39% 22% 4	4380
	21st to end	Day	35% 7% 24% 26% 7%	4814
June	1st to 10th	Day	34% 6% 15% 30% 13% 3	2660
	11th to 20th	Day	26% 4 16% 37% 13% 3	2660
	21st to end	Day	18% 3 15% 35% 21% 8%	2660
July	1st to 10th	Day	6% 2 7% 18% 29% 38%	4351
	11th to 20th	Day	8% 2 5% 13% 27% 45%	4345
	21st to end	Day	9% 2 7% 23% 38% 22%	4639
August	1st to 10th	Day	15% 2 6% 20% 34% 23%	4302
	11th to 20th	Day	15% 2 11% 39% 24% 8%	4065
	21st to end	Day	22% 2 11% 26% 31% 7%	4193
September	1st to 10th	Day	12% 2 9% 34% 28% 14%	2280
	11th to 20th	Day	24% 4 16% 26% 22% 7%	2280
	21st to end	Day	29% 4 15% 29% 18% 5%	2034
October	1st to 10th	Day	32% 6% 14% 28% 18% 2	1900
	11th to 20th	Day	39% 7% 17% 22% 13% 1	1900
	21st to end	Day	49% 7% 13% 22% 9%	1962
November	1st to 10th	Day	56% 8% 13% 18% 4	1655
	11th to 20th	Day	62% 10% 13% 12% 3	1520
	21st to end	Day	60% 8% 15% 11% 5% 1	1520
December	1st to 10th	Day	64% 6% 12% 15% 4	1520
	11th to 20th	Day	78% 5% 9% 6% 1	1928
	21st to end	Day	79% 4 7% 8% 1	2794
January	1st to 10th	Night	73% 7% 9% 9% 1	4406
	11th to 20th	Night	68% 5% 16% 9% 2	4420
	21st to end	Night	77% 6% 8% 8% 1	4765
February	1st to 10th	Night	55% 10% 19% 14% 2	2470
	11th to 20th	Night	48% 9% 18% 19% 5%	2404
	21st to end	Night	49% 10% 17% 19% 5% 1	1899
March	1st to 10th	Night	47% 10% 14% 24% 5%	3736
	11th to 20th	Night	33% 5% 20% 34% 8%	3490
	21st to end	Night	48% 8% 20% 21% 3	3643
April	1st to 10th	Night	41% 9% 21% 21% 7% 1	1900
	11th to 20th	Night	36% 6% 21% 23% 11% 3	1879
	21st to end	Night	31% 9% 20% 27% 11% 2	1752
May	1st to 10th	Night	33% 4 13% 32% 18% 1	2540
	11th to 20th	Night	17% 4 15% 41% 20% 3	2516
	21st to end	Night	25% 6% 36% 27% 5%	2762
June	1st to 10th	Night	35% 6% 14% 33% 9% 2	1520
	11th to 20th	Night	23% 4 21% 38% 14% 1	1520
	21st to end	Night	18% 3 13% 38% 22% 6%	1520
July	1st to 10th	Night	6% 2 8% 17% 32% 35%	2500
	11th to 20th	Night	9% 2 6% 16% 28% 39%	2492
	21st to end	Night	6% 1 8% 22% 40% 23%	2674
August	1st to 10th	Night	14% 2 5% 22% 35% 22%	2604
	11th to 20th	Night	15% 2 13% 41% 23% 6%	2839
	21st to end	Night	16% 3 14% 29% 31% 8%	3484
September	1st to 10th	Night	11% 3 13% 31% 28% 14%	1900
	11th to 20th	Night	22% 5% 14% 30% 18% 11%	1900
	21st to end	Night	23% 4 15% 30% 22% 6%	2142
October	1st to 10th	Night	30% 5% 12% 28% 24% 2	2280
	11th to 20th	Night	36% 6% 16% 26% 14% 2	2280
	21st to end	Night	39% 8% 14% 23% 15% 1	2636
November	1st to 10th	Night	50% 8% 15% 21% 7%	2444
	11th to 20th	Night	58% 9% 14% 15% 4	2660
	21st to end	Night	52% 9% 16% 17% 5% 1	2660
December	1st to 10th	Night	63% 7% 12% 14% 3	2660
	11th to 20th	Night	74% 8% 10% 6% 1	3276
	21st to end	Night	71% 6% 9% 12% 2	4862

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	34% 18% 16% 17% 13% 3	180
	11th to 20th	Day	36% 9% 18% 27% 9% 2	180
	21st to end	Day	25% 9% 24% 25% 16% 2	258
February	1st to 10th	Day	26% 15% 24% 22% 11% 2	370
	11th to 20th	Day	27% 16% 25% 22% 9% 1	365
	21st to end	Day	21% 19% 26% 25% 7% 2	375
March	1st to 10th	Day	21% 17% 28% 23% 9% 2	460
	11th to 20th	Day	20% 16% 23% 25% 13% 3	460
	21st to end	Day	22% 20% 27% 21% 9% 1	506
April	1st to 10th	Day	24% 22% 27% 15% 10% 2	460
	11th to 20th	Day	17% 27% 27% 17% 8% 4	452
	21st to end	Day	17% 23% 30% 20% 8% 2	460
May	1st to 10th	Day	16% 20% 30% 20% 11% 3	463
	11th to 20th	Day	19% 15% 31% 17% 14% 4	488
	21st to end	Day	13% 17% 31% 23% 12% 4	529
June	1st to 10th	Day	14% 20% 29% 19% 14% 4	490
	11th to 20th	Day	15% 24% 33% 16% 10% 2	490
	21st to end	Day	7% 17% 33% 26% 14% 4	490
July	1st to 10th	Day	5% 12% 42% 24% 14% 3	486
	11th to 20th	Day	5% 13% 36% 27% 16% 3	484
	21st to end	Day	3 11% 35% 24% 18% 8%	531
August	1st to 10th	Day	5% 9% 29% 24% 23% 10%	487
	11th to 20th	Day	2 9% 28% 29% 21% 11%	477
	21st to end	Day	8% 13% 27% 23% 20% 9%	539
September	1st to 10th	Day	4 12% 25% 27% 22% 9%	490
	11th to 20th	Day	10% 12% 26% 25% 23% 5%	490
	21st to end	Day	12% 14% 23% 28% 19% 6%	490
October	1st to 10th	Day	13% 13% 24% 24% 16% 10%	490
	11th to 20th	Day	15% 14% 22% 23% 19% 7%	490
	21st to end	Day	20% 16% 23% 21% 15% 5%	411
November	1st to 10th	Day	25% 12% 20% 27% 13% 3	260
	11th to 20th	Day	31% 11% 22% 24% 9% 3	180
	21st to end	Day	26% 8% 17% 29% 17% 3	180
December	1st to 10th	Day	24% 9% 24% 22% 14% 7%	180
	11th to 20th	Day	34% 10% 22% 26% 7% 1	180
	21st to end	Day	28% 12% 20% 27% 12% 1	198
January	1st to 10th	Night	28% 9% 21% 28% 12% 1	760
	11th to 20th	Night	28% 9% 16% 30% 14% 2	760
	21st to end	Night	23% 8% 17% 31% 18% 2	836
February	1st to 10th	Night	23% 12% 17% 33% 14% 1	760
	11th to 20th	Night	19% 13% 22% 29% 17% 1	744
	21st to end	Night	20% 14% 20% 33% 12% 1	628
March	1st to 10th	Night	18% 11% 21% 34% 15% 1	760
	11th to 20th	Night	14% 11% 23% 36% 14% 2	760
	21st to end	Night	16% 16% 27% 30% 10% 1	836
April	1st to 10th	Night	14% 16% 26% 29% 14% 1	760
	11th to 20th	Night	14% 17% 28% 25% 14% 2	751
	21st to end	Night	10% 16% 33% 27% 13% 1	612
May	1st to 10th	Night	10% 14% 31% 29% 15% 1	380
	11th to 20th	Night	9% 10% 28% 33% 17% 2	374
	21st to end	Night	6% 8% 35% 35% 14% 2	411
June	1st to 10th	Night	12% 12% 33% 28% 14% 1	380
	11th to 20th	Night	9% 17% 38% 27% 9%	380
	21st to end	Night	5% 13% 34% 31% 16% 1	380
July	1st to 10th	Night	3 8% 34% 36% 18% 1	370
	11th to 20th	Night	1 8% 41% 35% 13% 1	368
	21st to end	Night	2 9% 30% 38% 20% 1	416
August	1st to 10th	Night	2 6% 27% 41% 22% 3	422
	11th to 20th	Night	3 5% 19% 33% 32% 8%	564
	21st to end	Night	3 11% 28% 31% 23% 4	822
September	1st to 10th	Night	2 7% 27% 31% 30% 3	760
	11th to 20th	Night	6% 6% 26% 26% 31% 5%	760
	21st to end	Night	7% 7% 21% 34% 28% 4	760
October	1st to 10th	Night	11% 8% 19% 38% 21% 4	760
	11th to 20th	Night	13% 7% 20% 31% 26% 3	760
	21st to end	Night	17% 8% 24% 31% 18% 2	836
November	1st to 10th	Night	18% 9% 21% 37% 14% 1	744
	11th to 20th	Night	24% 9% 21% 31% 13% 1	760
	21st to end	Night	16% 8% 23% 34% 16% 3	760
December	1st to 10th	Night	24% 7% 20% 31% 16% 2	760
	11th to 20th	Night	26% 9% 18% 32% 15% 1	760
	21st to end	Night	28% 11% 20% 31% 9% 1	836

Page generated at 2024-10-29 22:22:58. Version ac07

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