Peachland
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Peachland clear sky chart from 2005-11-06 to 2024-10-20.

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	7% 9% 3 8% 5% 5% 5% 4 6% 7% 38%	101672
	Night	8% 11% 4 9% 5% 5% 5% 4 6% 7% 37%	97047
Transparency	Day	41% 6% 16% 21% 12% 3	101432
	Night	44% 7% 17% 20% 10% 2	96933
Seeing	Day	14% 17% 29% 25% 12% 3	15315
	Night	14% 11% 27% 30% 16% 2	23716

By Month

Percentage Cloud Cover NW (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	10% 19% 6% 16% 7% 6% 5% 5% 5% 4 17%	2321
	11th to 20th	Day	8% 17% 4 9% 8% 7% 4 4 4 7% 28%	2516
	21st to end	Day	15% 22% 5% 9% 6% 5% 5% 4 5% 6% 17%	2794
February	1st to 10th	Day	7% 16% 4 13% 9% 6% 5% 4 5% 5% 25%	1572
	11th to 20th	Day	7% 13% 3 9% 6% 6% 6% 5% 7% 7% 30%	1665
	21st to end	Day	6% 13% 5% 13% 9% 7% 7% 5% 6% 7% 21%	1541
March	1st to 10th	Day	4 13% 6% 13% 7% 6% 7% 5% 6% 7% 26%	3138
	11th to 20th	Day	3 10% 3 7% 5% 5% 5% 4 6% 7% 44%	3349
	21st to end	Day	8% 14% 4 10% 6% 7% 7% 5% 7% 7% 25%	4116
April	1st to 10th	Day	10% 12% 4 9% 7% 7% 5% 5% 7% 9% 25%	2280
	11th to 20th	Day	7% 12% 4 9% 6% 6% 7% 5% 7% 8% 29%	2259
	21st to end	Day	7% 11% 4 10% 6% 7% 6% 4 7% 8% 30%	2612
May	1st to 10th	Day	6% 9% 3 7% 5% 6% 6% 5% 7% 8% 38%	4420
	11th to 20th	Day	5% 7% 3 7% 6% 6% 6% 5% 8% 11% 36%	4377
	21st to end	Day	12% 12% 3 10% 6% 6% 7% 5% 6% 7% 26%	4813
June	1st to 10th	Day	15% 9% 3 9% 7% 6% 5% 4 5% 7% 30%	2865
	11th to 20th	Day	12% 9% 3 10% 7% 7% 6% 5% 7% 7% 28%	3040
	21st to end	Day	8% 5% 3 7% 5% 6% 6% 5% 5% 8% 41%	3040
July	1st to 10th	Day	4 3 1 5% 4 4 4 4 5% 6% 61%	4746
	11th to 20th	Day	3 3 1 3 3 3 3 3 4 5% 69%	4494
	21st to end	Day	3 2 1 4 3 3 4 3 6% 8% 62%	4790
August	1st to 10th	Day	2 2 1 3 3 4 4 5% 7% 8% 61%	4401
	11th to 20th	Day	3 4 2 5% 4 5% 5% 5% 7% 8% 53%	4282
	21st to end	Day	7% 5% 2 5% 4 4 5% 5% 6% 8% 49%	4243
September	1st to 10th	Day	5% 5% 3 6% 4 4 4 3 4 7% 55%	2280
	11th to 20th	Day	8% 7% 2 7% 5% 5% 5% 4 5% 6% 45%	2270
	21st to end	Day	10% 7% 2 6% 5% 4 5% 4 6% 6% 45%	2060
October	1st to 10th	Day	9% 9% 3 8% 4 5% 5% 3 5% 7% 42%	1900
	11th to 20th	Day	12% 8% 3 8% 6% 5% 5% 5% 6% 7% 36%	1845
	21st to end	Day	13% 10% 4 9% 6% 5% 5% 4 6% 7% 31%	1782
November	1st to 10th	Day	13% 14% 4 9% 6% 6% 5% 3 7% 7% 25%	1575
	11th to 20th	Day	10% 16% 4 11% 5% 5% 7% 4 6% 4 28%	1520
	21st to end	Day	10% 17% 6% 9% 8% 5% 4 5% 6% 6% 26%	1435
December	1st to 10th	Day	8% 14% 4 11% 9% 6% 5% 5% 7% 8% 25%	1330
	11th to 20th	Day	10% 17% 6% 12% 6% 5% 6% 4 6% 5% 23%	1682
	21st to end	Day	9% 16% 6% 14% 8% 7% 6% 4 6% 5% 18%	2319
January	1st to 10th	Night	11% 20% 7% 15% 7% 6% 5% 4 4 5% 16%	4618
	11th to 20th	Night	8% 17% 6% 12% 5% 4 4 3 6% 8% 26%	4382
	21st to end	Night	13% 26% 6% 10% 6% 5% 5% 4 4 4 16%	4862
February	1st to 10th	Night	10% 18% 5% 12% 7% 6% 5% 3 5% 6% 24%	2605
	11th to 20th	Night	8% 12% 4 8% 6% 5% 4 3 6% 7% 36%	2402
	21st to end	Night	6% 10% 6% 12% 7% 6% 6% 6% 7% 7% 27%	1913
March	1st to 10th	Night	5% 11% 4 8% 6% 6% 7% 5% 7% 8% 33%	3736
	11th to 20th	Night	5% 8% 3 7% 4 3 4 4 5% 7% 51%	3627
	21st to end	Night	7% 11% 3 10% 6% 6% 6% 4 7% 7% 32%	3537
April	1st to 10th	Night	6% 9% 4 9% 6% 6% 6% 5% 7% 9% 34%	1900
	11th to 20th	Night	5% 9% 4 9% 6% 7% 5% 6% 7% 6% 36%	1871
	21st to end	Night	6% 13% 3 8% 6% 5% 5% 4 6% 7% 37%	1565
May	1st to 10th	Night	7% 8% 3 8% 5% 4 4 3 6% 7% 44%	2540
	11th to 20th	Night	5% 5% 2 6% 4 5% 5% 5% 7% 11% 46%	2516
	21st to end	Night	8% 6% 3 6% 5% 4 5% 6% 7% 11% 40%	2762
June	1st to 10th	Night	10% 8% 3 8% 5% 4 4 5% 8% 9% 35%	1306
	11th to 20th	Night	8% 5% 2 8% 6% 5% 6% 5% 8% 10% 37%	1140
	21st to end	Night	6% 5% 2 7% 5% 4 5% 4 6% 6% 51%	1140
July	1st to 10th	Night	3 3 1 4 3 3 3 3 5% 6% 68%	2210
	11th to 20th	Night	2 2 1 3 2 3 3 3 4 6% 71%	2462
	21st to end	Night	3 2 1 3 2 3 3 3 4 6% 69%	2762
August	1st to 10th	Night	2 2 1 3 3 3 4 4 7% 8% 64%	2529
	11th to 20th	Night	3 3 1 4 3 4 4 3 6% 9% 59%	2545
	21st to end	Night	7% 4 1 5% 3 4 4 4 7% 8% 53%	3432
September	1st to 10th	Night	5% 4 2 5% 2 3 4 3 6% 8% 60%	1900
	11th to 20th	Night	7% 5% 2 5% 3 4 4 4 6% 7% 52%	1909
	21st to end	Night	8% 7% 2 6% 4 4 4 4 6% 8% 46%	2118
October	1st to 10th	Night	9% 6% 2 6% 5% 4 5% 4 6% 7% 47%	2280
	11th to 20th	Night	12% 8% 3 7% 5% 5% 5% 4 6% 5% 41%	2318
	21st to end	Night	13% 10% 3 8% 5% 4 5% 4 5% 7% 37%	2574
November	1st to 10th	Night	15% 13% 4 8% 5% 5% 5% 5% 6% 7% 29%	2501
	11th to 20th	Night	11% 16% 4 9% 6% 4 5% 5% 5% 6% 29%	2660
	21st to end	Night	11% 17% 5% 12% 6% 5% 5% 3 5% 6% 25%	2723
December	1st to 10th	Night	8% 17% 4 11% 7% 5% 5% 4 6% 5% 28%	2850
	11th to 20th	Night	12% 21% 6% 13% 7% 5% 5% 3 5% 5% 17%	3510
	21st to end	Night	12% 19% 7% 14% 6% 5% 6% 3 4 5% 18%	5342

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	64% 7% 15% 11% 3	2321
	11th to 20th	Day	56% 8% 18% 11% 2 5%	2540
	21st to end	Day	65% 7% 15% 10% 2	2794
February	1st to 10th	Day	59% 8% 13% 14% 6% 1	1572
	11th to 20th	Day	48% 11% 18% 16% 8%	1674
	21st to end	Day	56% 8% 16% 14% 5% 1	1541
March	1st to 10th	Day	50% 8% 15% 18% 8% 1	3138
	11th to 20th	Day	35% 6% 24% 30% 4	3349
	21st to end	Day	53% 7% 18% 12% 9%	4116
April	1st to 10th	Day	52% 8% 16% 17% 7% 1	2280
	11th to 20th	Day	47% 8% 14% 19% 11% 2	2259
	21st to end	Day	47% 7% 16% 19% 11% 1	2612
May	1st to 10th	Day	38% 6% 15% 26% 15%	4420
	11th to 20th	Day	35% 8% 19% 27% 11%	4380
	21st to end	Day	51% 7% 17% 19% 6%	4814
June	1st to 10th	Day	51% 5% 14% 16% 10% 4	2865
	11th to 20th	Day	49% 7% 15% 19% 9% 1	3040
	21st to end	Day	38% 6% 17% 22% 14% 3	3040
July	1st to 10th	Day	23% 4 8% 19% 29% 16%	4672
	11th to 20th	Day	17% 4 7% 20% 32% 20%	4416
	21st to end	Day	18% 4 12% 31% 26% 10%	4639
August	1st to 10th	Day	18% 4 12% 31% 29% 6%	4384
	11th to 20th	Day	26% 4 22% 32% 13% 3	4324
	21st to end	Day	30% 3 22% 28% 15% 1	4242
September	1st to 10th	Day	29% 5% 17% 27% 19% 3	2280
	11th to 20th	Day	35% 6% 16% 23% 18% 3	2270
	21st to end	Day	36% 6% 22% 21% 12% 1	2060
October	1st to 10th	Day	40% 5% 19% 30% 7%	1900
	11th to 20th	Day	44% 7% 18% 24% 7%	1845
	21st to end	Day	49% 8% 17% 21% 4	1782
November	1st to 10th	Day	53% 10% 16% 16% 5%	1575
	11th to 20th	Day	55% 11% 15% 13% 5% 1	1520
	21st to end	Day	56% 9% 16% 13% 6%	1435
December	1st to 10th	Day	57% 8% 16% 16% 2	1330
	11th to 20th	Day	60% 9% 18% 10% 4	1684
	21st to end	Day	61% 9% 15% 13% 3	2319
January	1st to 10th	Night	67% 7% 13% 10% 4	4618
	11th to 20th	Night	56% 8% 17% 12% 4 3	4420
	21st to end	Night	67% 7% 13% 9% 3	4862
February	1st to 10th	Night	60% 6% 15% 12% 7%	2605
	11th to 20th	Night	47% 7% 17% 20% 8%	2404
	21st to end	Night	53% 8% 15% 16% 8%	1913
March	1st to 10th	Night	43% 8% 17% 21% 11%	3736
	11th to 20th	Night	31% 7% 23% 32% 7%	3628
	21st to end	Night	47% 9% 17% 19% 9%	3537
April	1st to 10th	Night	43% 8% 22% 21% 6%	1900
	11th to 20th	Night	41% 7% 18% 21% 11% 1	1871
	21st to end	Night	43% 6% 18% 22% 10%	1565
May	1st to 10th	Night	36% 6% 12% 29% 17% 1	2540
	11th to 20th	Night	28% 8% 24% 29% 11%	2516
	21st to end	Night	36% 8% 26% 25% 5%	2762
June	1st to 10th	Night	40% 8% 15% 23% 9% 4	1306
	11th to 20th	Night	37% 5% 21% 27% 10%	1140
	21st to end	Night	29% 6% 22% 27% 13% 2	1140
July	1st to 10th	Night	19% 3 10% 22% 31% 15%	2175
	11th to 20th	Night	13% 5% 9% 20% 34% 19%	2417
	21st to end	Night	16% 3 13% 32% 22% 14%	2674
August	1st to 10th	Night	17% 4 11% 28% 36% 5%	2521
	11th to 20th	Night	21% 3 26% 34% 14% 3	2569
	21st to end	Night	27% 3 23% 30% 15% 1	3432
September	1st to 10th	Night	23% 3 18% 32% 19% 4	1900
	11th to 20th	Night	28% 5% 17% 26% 21% 4	1909
	21st to end	Night	34% 6% 22% 25% 10% 3	2118
October	1st to 10th	Night	35% 6% 20% 29% 10% 1	2280
	11th to 20th	Night	41% 7% 16% 26% 10%	2318
	21st to end	Night	45% 8% 17% 24% 7%	2574
November	1st to 10th	Night	52% 9% 17% 16% 6%	2501
	11th to 20th	Night	53% 10% 15% 14% 7% 1	2660
	21st to end	Night	58% 7% 17% 12% 5%	2723
December	1st to 10th	Night	58% 8% 14% 17% 4	2850
	11th to 20th	Night	66% 9% 14% 8% 3	3507
	21st to end	Night	65% 7% 14% 10% 4	5342

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	19% 17% 27% 19% 12% 6%	180
	11th to 20th	Day	21% 14% 26% 23% 13% 2	180
	21st to end	Day	21% 14% 31% 22% 10% 2	198
February	1st to 10th	Day	14% 23% 38% 19% 6% 1	232
	11th to 20th	Day	16% 19% 36% 23% 6% 1	365
	21st to end	Day	13% 20% 33% 23% 10% 1	368
March	1st to 10th	Day	15% 24% 32% 20% 8% 1	460
	11th to 20th	Day	14% 23% 28% 22% 11% 2	460
	21st to end	Day	17% 24% 30% 18% 9% 1	506
April	1st to 10th	Day	22% 23% 30% 16% 7% 1	460
	11th to 20th	Day	17% 26% 25% 18% 10% 2	452
	21st to end	Day	15% 22% 30% 20% 8% 3	460
May	1st to 10th	Day	15% 19% 33% 23% 9% 3	463
	11th to 20th	Day	16% 15% 25% 25% 17% 3	488
	21st to end	Day	15% 16% 27% 27% 13% 3	529
June	1st to 10th	Day	18% 15% 30% 24% 11% 1	695
	11th to 20th	Day	17% 19% 30% 21% 10% 3	870
	21st to end	Day	10% 13% 29% 28% 16% 3	870
July	1st to 10th	Day	7% 14% 31% 31% 16% 2	677
	11th to 20th	Day	6% 16% 24% 33% 16% 4	529
	21st to end	Day	6% 11% 26% 35% 18% 4	531
August	1st to 10th	Day	5% 9% 27% 34% 20% 5%	487
	11th to 20th	Day	6% 10% 28% 31% 20% 5%	477
	21st to end	Day	9% 16% 24% 31% 14% 5%	539
September	1st to 10th	Day	9% 17% 28% 28% 12% 7%	490
	11th to 20th	Day	12% 16% 25% 27% 16% 4	490
	21st to end	Day	17% 15% 31% 23% 11% 2	490
October	1st to 10th	Day	14% 16% 30% 23% 13% 4	490
	11th to 20th	Day	16% 21% 23% 24% 13% 2	441
	21st to end	Day	23% 15% 31% 21% 7% 2	297
November	1st to 10th	Day	16% 21% 35% 21% 7%	223
	11th to 20th	Day	18% 25% 28% 16% 10% 3	180
	21st to end	Day	18% 17% 27% 24% 10% 4	180
December	1st to 10th	Day	14% 16% 24% 23% 18% 5%	180
	11th to 20th	Day	12% 20% 34% 22% 7% 4	180
	21st to end	Day	13% 13% 33% 26% 13% 2	198
January	1st to 10th	Night	23% 13% 29% 24% 10% 1	817
	11th to 20th	Night	18% 10% 31% 27% 12% 1	760
	21st to end	Night	16% 10% 29% 30% 12% 3	836
February	1st to 10th	Night	20% 13% 28% 28% 9% 2	760
	11th to 20th	Night	14% 11% 31% 30% 13% 1	744
	21st to end	Night	14% 14% 22% 31% 17% 2	628
March	1st to 10th	Night	12% 11% 28% 29% 17% 3	760
	11th to 20th	Night	12% 13% 31% 29% 14% 1	760
	21st to end	Night	12% 12% 29% 31% 14% 2	836
April	1st to 10th	Night	13% 12% 27% 31% 14% 2	760
	11th to 20th	Night	10% 14% 29% 29% 16% 1	743
	21st to end	Night	11% 14% 32% 29% 13% 1	425
May	1st to 10th	Night	11% 11% 26% 35% 14% 2	380
	11th to 20th	Night	10% 7% 22% 37% 22% 1	374
	21st to end	Night	13% 9% 23% 32% 20% 1	411
June	1st to 10th	Night	12% 11% 34% 29% 12% 1	380
	11th to 20th	Night	10% 11% 36% 28% 14% 1	380
	21st to end	Night	6% 10% 31% 33% 17% 3	380
July	1st to 10th	Night	5% 8% 25% 41% 20% 1	370
	11th to 20th	Night	2 13% 28% 37% 19% 1	368
	21st to end	Night	5% 8% 24% 37% 23% 3	416
August	1st to 10th	Night	3 4 22% 39% 28% 4	378
	11th to 20th	Night	5% 3 22% 35% 31% 4	398
	21st to end	Night	6% 7% 24% 35% 24% 3	796
September	1st to 10th	Night	6% 9% 24% 33% 26% 4	760
	11th to 20th	Night	9% 7% 20% 26% 27% 10%	760
	21st to end	Night	11% 8% 24% 33% 20% 3	760
October	1st to 10th	Night	13% 8% 21% 33% 21% 4	760
	11th to 20th	Night	16% 11% 24% 30% 17% 2	758
	21st to end	Night	20% 13% 26% 26% 13% 3	792
November	1st to 10th	Night	21% 9% 31% 30% 8% 1	740
	11th to 20th	Night	19% 15% 26% 26% 11% 2	760
	21st to end	Night	18% 12% 29% 27% 10% 3	823
December	1st to 10th	Night	16% 10% 29% 29% 13% 2	950
	11th to 20th	Night	21% 10% 32% 27% 8% 1	950
	21st to end	Night	19% 10% 30% 30% 10% 1	1043

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